AOL’s AIM started out with enough popularity to freely ignore the need to integrate with other programs; now, it can be argued that AIM retains its relevancy by operating with other messaging programs like Google‘s Gmail chat and Apple‘s iChat. Other IM clients paired up with one another to increase usability, like when Microsoft and Yahoo became interoperable over two years ago.

But nowadays, social-networking offerings — like leaving messages on Facebook walls and receiving Twitter “tweets” from friends — compete with traditional instant-messaging programs. And advanced technology in mobile devices has helped these chats move from desktops to iPhones and BlackBerrys, where conversations can continue on-the-go, using mobile applications.

Three free programs — Meebo, Adium and Digsby — work by consolidating numerous messaging accounts into one combined program.

This week I tested three free programs that seem to acknowledge the fading star of isolated instant messaging, as we once knew it. Meebo, Adium and Digsby work by consolidating numerous messaging accounts into one combined program. Some of these include social-networking integration or even built-in email notifications, turning the service into a one-stop shop for online communication. The result can save people from choosing one IM system over another.

All three of these programs are straightforward and work without much effort or instruction. They require users to enter the user names and passwords to log onto each IM account, which may make some people uncomfortable, even though each site explains its privacy policy. Of the three, Digsby offers to integrate with the greatest number of programs all at once, including instant messaging, email and social-networking accounts. It also lets people handle email by deleting or sorting it directly in the IM window, which neither of the other programs does.

But Digsby isn’t yet usable on Macs or Linux, and Adium (the second-best offering) is available only on Macs. When used with the correct operating system, these programs perform as promised, easing communication overall and saving people the hassle of logging into various accounts — or missing out on chats with friends because of not signing into certain programs.

Meebo, www.meebo.com, is the only one of these three products that is completely Web-based. It works on all major browsers, including Internet Explorer, Firefox and Safari, and doesn’t require any installation — a plus for those who would like to be using instant messaging in the office but aren’t able to install software on corporate computers. It can log users into one of six messaging programs simultaneously, including Yahoo, Microsoft, AIM, Google, ICQ and Jabber.

I signed onto three instant-messaging accounts at once on Meebo by entering the username and password for each and selecting one overall “Sign In” button, which logged me into each program simultaneously and displayed all of my contacts in one condensed panel. Meebo can be configured to automatically launch within Firefox if a Firefox extension is downloaded.

Meebo.com is also usable on the iPhone and iPod Touch, allowing people to log into multiple accounts simultaneously from their mobile device. As of now, neither Adium nor Digsby has an application that allows it to work with the iPhone or iPod Touch.

Digsby, www.digsby.com, was a cinch to set up on my laptop, which was running Windows Vista. It walked me through the steps of adding accounts from instant-messaging programs, email accounts such as Gmail and Hotmail, and social-networking sites such as Facebook, MySpace and Twitter. Digsby works with IM and emails accounts from AOL/AIM, Yahoo, Microsoft and Google. Jabber, ICQ and Facebook chats also work with Digsby, along with IMAP and POP email accounts.

Once added, all of these accounts are represented in one clean panel. These consolidated communication programs saved me many extra clicks on my computer over a weekend, and I easily chatted with friends while checking messages. New emails received in my Gmail account were visible in a preview panel that popped up when I moved my cursor over the email account name. Right within this email preview panel, I could delete or archive each message; I was also able to mark a message as read or report it as spam. I performed all of these email tasks without opening my Gmail account in a browser or email client. Shortcuts in this preview panel labeled Open, Compose and Inbox sent me to my browser to perform these more-involved tasks.

This in-line functionality also applies to other email accounts, according to Digsby. But though I could see a tally of newly received Hotmail messages in my Digsby preview panel, these messages weren’t as interactive as those received in my Gmail inbox.

Digsby also tracks Twitter alerts and timelines, as well as Facebook newsfeeds and alerts — including posting notifications in your Digsby panel whenever someone “friends” you on Facebook.

Adium, www.adiumx.com, wins points for cuteness. The downloaded program is represented by a goofy, green duck, which plops itself in the Mac operating system dock and closes its eyes when not in use. When new messages are received via Adium, this duck flaps its wings until you open the message. The Adium user interface incorporates sleek visuals, such as status windows that gracefully float above user names whenever a cursor moves over these names.

Adium works with AIM, ICQ, .Mac, Jabber, Google Talk, Windows Live Messenger and Yahoo Messenger. Adium supports new email notifications for some accounts, but doesn’t enable reading or sending email within the program. Instead, it offered to open my account via the browser or using Microsoft Entourage on the Mac. Social networking is limited to MySpace IM on Adium, though the next version will support Facebook Chat.

Adium organizes multiple conversations using tabs stacked at the bottom of a chat window. Icons line the top of each chat window, such as a file icon for transferring files and a lock that switches a conversation to be encrypted and off-the-record. Any conversation that isn’t designated encrypted is automatically stored in a table of Adium transcripts, which can be sorted by To, From or Date. Transcripts can be sorted using rough timelines like “within the past two weeks” or “since yesterday.”

I saved myself time and mouse clicks by using these three consolidation programs, though I preferred Digsby in the end because of its intuitive email integration. These programs will help to take down the instant-messaging barriers that have become turn-offs over the past couple years, and may better integrate IM with the social networks and mobile devices that are on the rise.

Edited by Walter S. Mossberg

Write to the Mossberg Solution at mossbergsolution@wsj.com

This will continue to be obvious even after Apple (AAPL) announces “iPhone 2.0″ at this week’s conference for Macintosh and iPhone software developers. This new device, of course, is the updated version of the path-breaking model that was launched a year ago amid a blizzard of hype.

I continue to be an iSkeptic of sorts. I don’t own an iPhone, and even if all the rumored new features appear they probably won’t be enough to overcome Apple’s still-unfortunate choice of AT&T (T) as its telecom carrier partner.

True, no other device does exactly what the iPhone does. Conversely, the iPhone doesn’t come close to matching the most valuable features of the devices I do use, namely Research in Motion’s (RIMM) BlackBerry Curve and Nokia (NOK) N95. Let’s look at each to see why.

My primary device is the BlackBerry, for two major reasons. First, using T-Mobile’s clever UMA technology, which does a voice hand-off from cell to WiFi–something that works on several T-Mobile handsets, but not the BlackBerry Curve on other networks–I can use the phone (and save cell minutes and money) using voice over IP. This is especially helpful at home where the cell signal is weak, but also helpful given that it works with just about any WiFi network. AT&T hasn’t built UMA into its own network, and Apple’s first iPhone did not permit VoIP in any case.

Just as important, the BlackBerry’s physical keyboard–small keys that are nonetheless accurate and have a nice tactile response–makes it a mostly excellent email tool.

Mostly, but not completely–because BlackBerry’s email capabilities are designed around Microsoft Exchange. I do use Exchange for one email account, but IMAP on several others. And the BlackBerry has no IMAP client software that even understands how to flag a message as having been replied to, much less an understanding of folders.

I would pay good money for a solid IMAP client for the BlackBerry, but no one seems to care enough to create one. I suspect there’s a serious market for the first company that does this.

If the iPhone had a tolerable keyboard–and I find the virtual, screen-bound keypad nearly useless–it would be a vastly better email device than the BlackBerry, especially because it absolutely gets IMAP and is about to work with Exchange servers.

The iPhone’s camera is roughly equivalent to the one on the Curve: inadequate at best, with relatively low resolution and no video mode. Nokia’s N95, by contrast , is a great camera, with a 5 megapixel still resolution and 30-frame-per-second VGA video recording and playback.

I can “tether” the N95 to my laptop and use it as a modem; no such common-sense usage with the iPhone. The N95 also has WiFi (and handles VoIP) and 3G, invaluable for international travel; strong rumors say the iPhone will remedy the 3G situation in the new version.In fact, the N95 has almost too many high-end features, a key reason it has especially poor battery life. GPS is another N95 advantage; again, there are strong indications that the iPhone will also have it–and the large screen on the Apple device makes maps a joy to use and view.

I do love the iPhone as a media playback device, however. That’s why I bought an iPod Touch, which is roughly the same size and has become my portable media system of choice, especially on airplanes. And when it comes to Web browsing, it’s absolutely no contest: The iPhone blows away the Blackberry and N95.

Apple raised the bar in a serious way when it comes to software. While Nokia’s operating system has been much more open than the iPhone’s (or BlackBerry’s)–something Apple has halfway remedied with its semi-open new development model–Nokia has a long way to go to get even close to Apple in basic usability. The BlackBerry is quite easy to use, but still far behind Apple in many respects.

Will I buy an iPhone when the new models hit the stores? I still don’t know. Apple’s insistence that legitimate software will only be available through its online store is part of the company’s typical arrogance. And its continued lock-in with AT&T is close to a deal-killer no matter how good the device may be.

Of course, you can “jailbreak” even the current iPhones. And it’s looking as though the new ones will be even more malleable, at least theoretically.

No matter what Apple introduces, the compromises will continue, however. But the time is almost in sight when we’ll have just about everything we want–not just what we absolutely need–in our handhelds. Not real soon now, but sooner than we might expect.

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 downloading email to both home and work computers, the differences in Treo models and transferring files between Windows systems.

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

I want to download all my daily emails to both my home and office computers, which are both Dells. I am told that, in order to achieve this, I have to instruct my email program to keep my email on the server. How do I do that?

With most corporate email systems, and with a type of consumer email called “IMAP,” email is synchronized among your computers. But many home users have a type of email called “POP,” which isn’t synchronized.

To get the same email messages on multiple machines, POP users have to instruct the email software on each computer not to delete messages from the remote server when they’re downloaded to one of the PCs. That way, they remain available for downloading onto your other PCs. This is generally accomplished by turning on an option in the settings for your email account, which can be a convoluted process.

In Microsoft Outlook 2003, go to the Tools menu, select Email Accounts, then pick “View or Change Existing E-mail Accounts.” Select the account you want, click Change, then, in the next window, click More Settings. In the next window, select the Advanced tab and click in the checkbox called “Leave a copy of messages on the server.” Then click OK, then Next, and Finish, in the windows that follow. Whew.

In Outlook Express 6, it’s a little easier, but not much. On the Tools menu, select Accounts, then Mail, then the account name you want. Click on Properties, then select the Advanced tab. Check the box next to “Leave a copy of messages on server.” Then click OK, OK and Close.

Both programs allow you to set a number of days for the messages to stay on the server. I recommend setting that to 1 or 2, which is long enough so they’ll be downloaded to all your PCs, but short enough so your mailbox on the server won’t exceed its limits. I also suggest clicking an option that does delete from the server any messages you actually delete on any of your PCs. You’re not likely to want to see those everywhere.

Since the Treo 600 is much cheaper than the newer Treo 650, I am considering getting a 600 instead of a 650. What will I be missing if I do so?

The two models are very similar in their look and feel and their core functionality. The key differences are that the 650 has a much better screen, a removable battery, a slightly better keyboard and a better (but still not great) built-in camera. It also has Bluetooth wireless networking, and it is built much better, because Palm is using a different contractor to assemble the 650 than the one it used for the 600, which was plagued by quality complaints.

I am about to buy a new computer running XP Pro. I want to selectively transfer some, but not all, files from my old Windows 98SE computer over a cable. What is the best program for the job?

I generally recommend IntelliMover by Detto, at www.detto.com. Note, however, that IntelliMover won’t move application programs — only files, like Microsoft Office documents, pictures, songs, etc. If you want to move programs, try Alohabob PC Relocator, at www.alohabob.com.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, 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