Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about using cellphones as modems for laptops, storing personal files from office computers and buying an ultralight laptop.

I would like to buy one of the new phones that run on high-speed networks from Verizon or Sprint and use it as a modem with my laptop. Do the phone carriers charge extra for this?

Yes, both Sprint and Verizon do impose an extra monthly charge for using this feature of phones like the new Treo 700p. They reason that if you access the Web on your phone, which has a limited browser and no hard disk to store large downloads, you aren’t likely to use a huge amount of network capacity. But once the phone is used as a modem with a laptop, it becomes very much like their laptop cards, for which they do charge a hefty monthly data fee. For instance, Sprint charges $40-$50 a month extra for unlimited data connections using the Treo 700p as a modem, depending on the length of your contract and whether you also have a Sprint voice plan.

I’m changing jobs after 10 years. What is the best way to take my personal files with me? I know Microsoft Office documents can be readily put on any storage media, but what about emails and contacts stored in Outlook? Can you offer some advice on how to best accomplish this move? (I am not taking any company property.)

Since this isn’t a legal column, I won’t weigh in on what constitutes personal data on a company computer. But it’s pretty easy to move your email and contacts from your Outlook to another copy of Outlook on a new PC at your home or your new office. In Outlook, go to the File menu. Select “Import and Export… “. Choose “Export to a File.” Then select “Personal Folder File (.pst).” Next, choose the Outlook folder containing the data you want to export. This could be your email Inbox, or any other email folder, or it could be the Contacts folder, or any other non-email folder, like Calendar. Finally, select the location where you want to save the exported data. If you are using a USB drive, use the “Browse” button to locate it. Then, hit “Next” and then “Finish.” Repeat the process for each folder you want to export. At the new computer, insert the drive with your exported data, launch Outlook, bring up “Import and Export…” again, and this time select “Import from another program or file.” Follow the steps to import a .pst file.

I am interested in purchasing an ultralight laptop computer for traveling, something I could carry in a messenger bag. I wish to use it mostly for Internet connectivity and word processing. I might even sneak in a DVD for use on the plane. I have looked at the Sony Vaio TX series and the Dell X-1. Are there others in the same size/weight category I should consider?

Yes. You might look at the HP Compaq nc2400 or the Lenovo ThinkPad X60 or the Gateway NX100X or the Toshiba Portégé R200. Except for the HP, none of these has an internal DVD drive, though, so depending on how important that is to you, you might have to spend more or go up to around four pounds. The Sony TX is excellent and combines low weight with an internal DVD. But it’s expensive. Other options for ultralights with internal DVD drives are offered by Fujitsu and Panasonic. I haven’t reviewed all of these, so I can’t recommend them all. My review of the Sony TX is at: http://ptech.wsj.com/archive/ptech-20051006.html. My review of the HP nc2400 is at: http://ptech.wsj.com/archive/ptech-20060518.html. My review of the ThinkPad X60 is at: http://ptech.wsj.com/archive/ptech-20060420.html.

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Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

These latest models aren’t quite as small as the teeniest laptops available, like Sony‘s Vaio TX series, which are flaunted at airports like skinny fashion models at a photo shoot. But the new contenders have larger screens than the TX and cost less than the $2,300 or more that the Sony commands.

These new laptops all have screens that measure 12.1 inches diagonally. All hover around four pounds, though in some basic configurations some can weigh as little as three pounds. Even well equipped, they cost between $1,400 and $1,700.

Gateway began the most recent wave with a slender model released earlier this year, the NX100X, starting at just $1,400. But, unlike the Sony TX and other new models, it lacks an internal DVD drive.

I’ve been testing and comparing two newer entries that do pack an internal DVD drive into their small cases. One is the first ultraportable laptop from Hewlett-Packard in years, the Compaq nc2400. The other is one of the first crop of portables to be sold in the U.S. under the brand name of Lenovo, the Chinese computer giant, which now owns the IBM ThinkPad line of laptops. It’s called the Lenovo 3000 V100.

The H-P Compaq NC2400, already shipping, can be bought for as little as $1,549. A stripped-down model of the new Lenovo 3000 V100, which will be available soon, can be had for a mere $1,099. But the configurations of both computers I tested — selected and provided by the manufacturers — each cost precisely $1,649.

I like both of these machines, despite the fact that the H-P and Lenovo marketing people apparently skipped the class in business school about giving products simple, memorable names. You won’t go wrong with either of these laptops. But for their identical price, you get very different computers.

Based on “speeds and feeds,” the raw specs of a computer, the Lenovo offers much more than the H-P. But based on the key components of road-warrior mobility — weight, size and battery life — the H-P crushes the Lenovo.

Lenovo 3000 V100

The H-P is a dark-gray and black model that feels svelte, but solid. It is less than an inch thick, and the version I tested, with an extra-strength six-cell battery that protruded from the rear, weighed in at 3.8 pounds.

The Lenovo has a silvery lid and a black body that manages to look bulkier than it really is. It’s 1.25 inches thick, and the version I tested, which also had an extra-strength, six-cell battery that protruded from the rear, weighed 4.1 pounds.

The H-P also has a smaller footprint for a desktop or airline tray — 11.1 by 8.38 inches vs. 12 by 8.9 inches for the Lenovo.

I put the two contenders through my harsh battery test, where I turn off all power-saving features and keep the hard disk working.

The Lenovo’s battery lasted two hours, 41 minutes, an OK time for a little laptop. In more normal use with power saving on, it would likely approach 3.5 hours.

But the H-P Compaq nc2400 blew away the Lenovo on battery life, with a startling endurance of four hours, 27 minutes. This performance, one of the best I have ever recorded, suggests that with its power-saving features turned on, the little H-P could allow you to work for six hours straight without recharging.

On speeds and feeds, however, the tables are turned. The H-P I tested has a relatively wimpy Intel Core Solo processor running at 1.2 gigahertz, though it can be ordered with faster processors. The Lenovo has an Intel Core Duo, with the equivalent of two processors, running at two gigahertz. The H-P has 512 megabytes of memory; the Lenovo has one gigabyte — twice as much. The H-P has a 40 gigabyte hard disk. The Lenovo’s hard disk is 100 gigabytes.

I didn’t find the H-P sluggish at the typical, mainstream tasks I threw at it. But for the same price, you get much more power and storage in the Lenovo.

About the only basic spec where the H-P beats the Lenovo is screen resolution. The H-P’s is slightly higher — 1,280 by 800 compared with 1,200 by 800 on the Lenovo.

Both machines include built-in fingerprint readers, but the Lenovo also has a built-in camera, which the H-P lacks. The Lenovo also uses the same keyboard found on the ThinkPad line, which I regard as the best on any laptop.

The Lenovo lacks the rugged magnesium frame and hard disk shock-protection features that were pioneered on the ThinkPad. The H-P does have versions of these protective features. And the Lenovo uses a typical touch pad to control the cursor, while the H-P uses a mid-keyboard pointing stick.

With these two contenders, your $1,649 can either buy you a somewhat smaller machine with bare-bone specs but fabulous battery life, or a better-equipped model that’s a bit bigger and much more power-hungry.

Take your pick.

• Email me at mossberg@wsj.com.

I’ve been testing two new small and light laptops from these companies: the Sony Vaio SZ160, and the Lenovo ThinkPad X60s. Both weigh in at under four pounds, so they won’t break your back when you tote them on the road. But each has plenty of power, decent battery life and a rich set of features. And, despite their small size, these machines are capable of serious work, partly because both use Intel’s new Dual Core processor, which packs the equivalent of two processors into one.

I like both machines, but they have different benefits and downsides. The ThinkPad is the latest entry in a long line of small, rugged laptops with great keyboards and strong battery life. It has a speedy, optional, internal cellphone modem for connecting to the Internet over a cellphone network. But it lacks an internal optical (CD or DVD) drive.

At the cost of just a little more weight and size, the Sony I tested includes an optical drive and a bigger screen, but it lacks a cellphone modem and has weaker battery life than the Lenovo configuration I tested. For enhanced security, both laptops have built-in fingerprint readers that can bolster or replace typed passwords. Neither is a bargain-basement laptop. The Sony SZ series starts at $2,000, and the ThinkPad X60 series starts at $1,900. They come in many different configurations, and thus many different prices. The ThinkPad X60s I tested, which included a cellphone modem, an extra-strength battery and a dock with an optical drive, costs $2,300. The Sony SZ I tested, which didn’t include a dock, an extended battery or a cellphone modem — but did have that internal optical drive — costs $2,500.

The Lenovo ThinkPad X60s

The Thinkpad X60S I tested weighed 3.46 pounds, while my Sony SZ160 test model weighed just 3.72 pounds, even with the bigger screen and optical drive. The ThinkPad is 10.5 inches wide by 8.3 inches deep, and it’s between 0.8 inch and 1.11 inches thick. The Sony is 12.5 inches wide by 9.3 inches deep, and it’s between 0.9 inch and 1.3 inches thick. The Sony’s larger dimensions are mainly a result of its bigger screen — 13.3 inches, versus 12.1 inches for the Lenovo. The Sony screen is also higher resolution.

I put both laptops through my usual tough battery test, wherein I turn off all power-saving software, crank up the screen brightness to the max, turn on the wireless networking, and then play an endless loop of music.

My test ThinkPad, with its double-capacity battery, lasted a very impressive four hours and 49 minutes. In normal use, with power-saving turned on and a more typical work pattern, I’d expect it to last six hours or more, which is excellent. My test Sony, which had a normal-size battery, lasted just three hours and two minutes, even though the machine was running on its so-called Stamina setting. In normal use, the Sony would likely top four hours. Presumably, a Lenovo with a standard battery would do worse, and a Sony with an extended battery would do better.

Neither can match Apple when it comes to the quality of its built-in software. Lenovo’s is too geeky and is aimed more at corporate than consumer customers. Sony’s is more consumer-oriented, but it’s inconsistent and confusing.

The ThinkPad X60s, like its predecessors from IBM, is compact and rugged, with strong hinges and the best keyboard in any laptop. It has both built-in Wi-Fi wireless networking and a built-in cellphone modem that works on Verizon’s speedy EV-DO network.

My test machine worked well on all the typical computing tasks most people do, but there was one small defect in a Lenovo-supplied wireless software program that kept turning off the Wi-Fi. The company says this problem appeared only in early models like mine and has been fixed. Overall, the quality seemed as good as when IBM was making the machines.

The Sony Vaio SZ160

But the Thinkpad X series really should have an internal optical drive by now. When it was introduced, few ultra-small laptops had them, but since then Sony and others have figured out how to install optical drives in even smaller boxes.

The Sony SZ series is interesting because, while it’s not Sony’s smallest or lightest line, it packs a larger screen and an optical drive into a package that’s under four pounds. Like the Lenovo, it worked well at all typical tasks.

The SZ’s biggest innovation is that it has two graphics systems and the aforementioned “Stamina” mode, controlled by a switch, which allows you to use the weaker graphics hardware to save battery power. Its biggest downside is that its optional cellphone modem (available this summer in a pricier premium model I didn’t test) works on Cingular’s EDGE network, which is only about a seventh as fast as the Verizon network Lenovo uses.

You won’t go wrong with either of these well-designed laptops. For road warriors, they are worth their hefty price tags.

• Email me at mossberg@wsj.com.

All of this makes carrying a large laptop less and less practical. But the smallest, lightest models have historically included design compromises that have ruled them out for many users.

Lately, however, the computer industry has been beefing up the capabilities of the so-called ultralight models. They cover all the key bases for mainstream travelers. And you can actually use them in coach.

I’ve been testing two good examples of this new class of full-featured ultralight laptops, the Sony Vaio T250 and the Fujitsu LifeBook P7010. I like both machines, but there are some key differences between them.

The Fujitsu costs less, at $1,999 after rebate, yet it boasts more and better features, including a larger hard disk and more ports and connectors. But the Sony, which costs $2,199 after rebate, wins this comparison in three areas that matter greatly to travelers: It’s a bit lighter, a bit thinner, and it has much better battery life.

The Fujitsu LifeBook, top, and the Sony Vaio

And the Sony’s screen, while the same size as the Fujitsu’s, doesn’t extend upward as far when fully opened, making the Sony a bit easier to use when you’re seated behind a serial recliner.

Both laptops weigh only about three pounds and have very small footprints that fit easily on a coach-seat tray table. But, unlike past generations of light laptops, these two models include internal disk drives that can play, and record, both DVDs and CDs. So you can install software from a CD or watch a DVD on the plane.

The two laptops use the same Intel processor, a power-saving Pentium M running at 1.2 Gigahertz. That’s plenty of processor for common tasks. And both have built-in Wi-Fi wireless networking.

Each has a decent 512 megabytes of memory, though, in both cases, up to 64 megabytes of that memory can be siphoned off by the identical Intel graphics chips they use. The Fujitsu’s hard disk holds 80 gigabytes, the Sony’s 60 gigabytes.

Both laptops have wide-angle screens that measure 10.6 inches diagonally. That’s very small by today’s standards. But size isn’t everything. A high screen resolution can squeeze lots of material onto a small display, and both the Fujitsu and Sony sport a resolution of 1,280 by 768, which does the trick.

Also, both of the screens are of the new, reflective type that delivers great contrast, though that can be a problem if there’s a strong light source over your shoulder.

Because of their small size, both models have slightly cramped keyboards. But I found both quite usable. I liked the feel of the Fujitsu’s keyboard slightly better than the feel of the Sony’s, though the Sony has larger right-hand Backspace, Enter and Shift keys.

Another limitation common in past generations of little laptops has been battery life. To keep weight and size down, manufacturers have often scrimped on battery size. But these two models boast battery life that would allow for nearly constant work on a cross-country flight.

I put both machines through my tough battery test, where I turn up the screen brightness all the way, disable all battery-saving controls, and play an endless loop of music to keep the power-hungry hard disk spinning. The Fujitsu’s battery lasted a very respectable three hours and 38 minutes, meaning that in a more normal usage pattern, with battery-saving controls turned on, it would likely approach five hours of life on a single charge.

But the Sony’s battery life was truly amazing for such a small machine. In my test, it lasted four hours and 25 minutes, or 22% longer than the Fujitsu. In more normal use, with battery-saving controls enabled, the little Sony could likely approach six hours of life.

The Fujitsu weighs 3.3 pounds and is 1.26 inches thick, 10.27 inches wide and 7.83 inches deep. The Sony weighs 3.04 pounds and is one inch thick, 10.7 inches wide and 8.1 inches deep — mainly because its battery protrudes from the back a bit.

Both laptops have two USB 2.0 ports; a PC card slot; and a Firewire port (also called “1394″ or “iLink”). And each has a standard video-out port for use with desktop monitors, and a touchpad for controlling the cursor.

But the Fujitsu also has a built-in fingerprint reader, which can lock out anyone but people whose fingerprints it recognizes. And it has an S-video port, for hooking up to a TV, and a multiplicity of slots for camera memory cards. It can handle the popular Secure Digital and Compact Flash types of cards, as well as the Memory Stick Pro cards that are mainly used by Sony cameras.

In Sony’s typical proprietary fashion, the T250 can handle only Sony’s own Memory Stick Pro cards. And the Sony lacks S-video and a fingerprint reader.

If the extra features and lower price matter a lot, go with the Fujitsu. But if lower weight, thinner size and better battery life are your key considerations, the Sony is the better choice.

Write to Walter S. Mossberg at mossberg@wsj.com