One welcome sign is an effort by companies trying to improve Microsoft Corp.’s (MSFT) Windows Mobile operating system, which has a reputation for confusing navigation and hasn’t had a major update recently. Kinoma Inc., for example, recently released an application called Kinoma Play that runs on Windows Mobile devices and gives users a markedly better way of handling photos, videos, music and Web browsing.

The HTC Touch Diamond, due out this month from Sprint, tries to hide Windows Mobile software.

This week, I tried yet another software program that is designed to run on top of Windows Mobile software. But this time, the software is at the heart of a device designed by the same company: HTC Inc. I tested the HTC Touch Diamond, due out from Sprint (S) sometime this month for $250 (after a $100 mail-in rebate) with a two-year contract.

Taiwan-based HTC started out in 1998 as a maker and designer of mobile devices for other companies. A year ago, HTC launched the first device under its own name in the U.S., and now, Sprint, AT&T (T) and T-Mobile (DT) sell HTC-branded devices. The Diamond incorporates HTC software, as well as software from Sprint, MobiTV, TeleNav and others. But it isn’t a stretch to imagine HTC trying to create a fully end-to-end model (hardware and all software) in the future.

The Diamond has a touch screen, but it’s smaller than Apple’s (AAPL) iPhone — 2.8 versus 3.5 inches. This screen lacks the iPhone’s multitouch functionality, and its smaller size robs space used for touch gestures like flicking or scrolling with a finger. Yet like the iPhone, it relies solely on an on-screen keyboard for all text entries. Even with the Diamond’s stylus, the keyboard felt small and cramped. Using just your fingertips was next to impossible.

After using the Diamond for a week, I can say that despite its handsome TouchFLO 3D software and animated icons like photos that flip from one to the next with a flick of finger, this device failed to disguise the frustrating interface of Windows Mobile often enough for my taste.

It reminded me of the brown paper bag book covers my Dad helped me make for schoolbooks when I was a kid: They looked great on the outside, felt sturdy and clean and created a blank canvas for homemade doodles that were often more interesting to me than the books they covered. But my book covers couldn’t change what was underneath; pages of frustrating algebra were just a flip away.

HTC’s sleek software tries to hide Windows Mobile, but menus from the Microsoft operating system are constantly popping up. HTC’s email program, for example, is represented by an animated envelope icon that, when selected, cleverly flips twice before sliding an email message half-way out and giving you a three-line peek at what’s inside. If only reading and responding to email were half as entertaining. Selecting the animated envelope opens the old, cumbersome Windows Mobile email program.

Also, the touch capabilities of the Diamond’s screen didn’t work as well as they should. Finger flicks that should have scrolled through lists instead seemed to select individual items in a list, as if they were sticky.

The Diamond isn’t all bad, of course. Plenty of people will like its smaller size because the iPhone and RIM’s (RIM) BlackBerrys seem too large and brick-like to hold up to an ear for phone calls. Next to my BlackBerry Curve, the Diamond was of comparable thickness but measured smaller in width and length.

Despite its size, the Diamond is packed with features. It has a 3.2-megapixel camera with autofocus that doubles as a camcorder, and comes with four gigabytes of internal memory and a removable battery. I taped short videos — something the iPhone can’t do — and found the sound and video footage to be adequate.

HTC touts the Diamond’s browser, which is based on the Opera browsing engine but is designed for HTC. It opens Web pages in views that fit the screen and text is automatically resized as users zoom in or out, though this resizing was sometimes slow.

Unlike the iPhone, Web sites that are opened on the Diamond’s browser don’t resemble the actual site as you would see it on your computer. I opened CNN.com (TWX) and WSJ.com (NWS), two sites that are packed with text and graphics on a regular browser. On the Diamond, they quickly were rendered in list format with mostly text-only. I easily touched the screen to follow links to full stories.

Like the iPhone, the Diamond has an accelerometer, though it’s called the “G-Sensor.” When it worked, this feature flipped the screen to match the horizontal or vertical direction in which the device was being held. Photos flipped instantly, but the Diamond’s G-Sensor took almost three full seconds to respond as I flipped from vertical to horizontal while using the browser. And some Web sites didn’t respond to the G-Sensor flips at all.

A special YouTube application developed by HTC was easy to find on the device and worked quickly. My videos were organized into categories for All, History, Bookmarks and Search, though this last category required using the finger-fumbling keyboard. In one step, I emailed a link from a YouTube video to a friend using the device, with a still shot from the video included in the message.

Overall navigation on the Diamond isn’t as intuitive as on the iPhone or iPod Touch, nor was it as easy as on a touch-screen Windows Mobile device running the Kinoma Play application. The iPhone and iPod Touch use quick double-taps on touch screens to zoom in or out, and multitouch capabilities resize images with pinching gestures; Kinoma Play uses a long touch to zoom in. The Diamond used double tapping on some screens, but not enough for me to grow comfortably reliant on it. A small, circular pad beneath the device’s touch screen provided a more dependable method for zooming in or out of screens: tracing the perimeter of this circle clockwise with a finger zoomed in; counterclockwise zoomed out.

The HTC’s software animation is put to good use on its Weather screen. Here, animated illustrations of each day’s weather appear on the screen: suns spin, clouds move in, rain appears to fall. Even moons appear on the device at night to accurately reflect the weather in a city at a specific time.

It is exciting to think about other mobile-phone companies giving better software a real try, especially those that attempt to improve Windows Mobile. But HTC’s Touch Diamond doesn’t hide the outdated operating system well enough or often enough for a user to want to buy a whole new mobile device.

Edited by Walter S. Mossberg

• Email us at mossbergsolution@wsj.com. Find this and other columns and videos online free at the All Things Digital Web site: http://walt.allthingsd.com

MobiTV, from MobiTV Inc., www.mobitv.com, gives people a way to watch television on their cellphones.

For lovers of portable video, the arguments in favor of TV on phones are speed and convenience. Rather than waiting to download movies, video podcasts and TV shows to a computer and then to transfer them to a portable player like an iPod, some would rather see current, live content streamed onto the device they already carry — their cellphone — whenever they want, wherever they are.

Live TV on cellphones isn’t new. We first tested it in 2004. But it was awful then, choppy and almost unviewable, because the cellular networks were too slow and the phones were too wimpy. So I decided to try it again.

Many cellphones are capable of displaying streamed television using built-in services, but few people are aware of these capabilities and not every phone will work as well as the next. The best results are delivered on devices with good quality screens that can retrieve and display the content using high-speed networks.

I used a mobile content-streaming service called MobiTV on three phones serviced by two carriers, Sprint Nextel Corp. and AT&T Inc.’s Cingular Wireless, watching a variety of shows on screens smaller than the palm of my hand. Monthly usage for watching cellphone TV with these two carriers costs about $25 and $30, respectively, on top of your voice plan. MobiTV is compatible with more than 150 handsets, offering roughly 40 channels — about half of which show live content like that found on your home TV.

All in all, MobiTV offers a fun and simple solution for people seeking TV on the run. High-quality images appeared on screen just moments after I opened the MobiTV application and an on-screen guide labeled each channel. TLC, ESPN, The Discovery Channel, The Oxygen Network and major news channels are entertaining enough. And though my eyes hurt after 30 minutes of watching such a small screen, I only ran into a few other snafus: on-screen images disappearing while audio continued, certain channels cutting out and lips moving out of sync with audio. In more cases than not, these instances were rare or corrected themselves in seconds.

Other carriers offer video clips that might easily be confused with MobiTV Inc.’s technology. Verizon Wireless, for example, offers its V Cast service. But V Cast requires that you download clips onto your device. Sprint and Cingular also offer video-on-demand options. But the MobiTV service streams content onto your phone, showing it just about a minute later than the same content on live TV.

If you don’t use Sprint or Cingular and you’d like to download MobiTV to your standard cellphone, or to your Palm or Windows Mobile smart phone, you can do so through third-party vendors like Handango.com; these options can be found on www.mobitv.com. Vendors charge about $10 a month on top of any data charges that you might owe your carrier.

MobiTV’s service includes a channel guide.

Sprint and Cingular encourage you to buy an unlimited monthly data plan in addition to your voice plan if you’ll be watching TV on your cellphone. Sprint calls its live-TV service Sprint TV Live — though it’s really MobiTV beneath the covers — and offers TV-inclusive data plans for $15, $20 or $25. These return 8, 13 and 25 channels respectively. Sprint’s exclusive content includes the NFL network. To further confuse matters, you can also buy stand-alone Sprint TV Live on top of those three data plans; it costs about $10 monthly. Cingular charges users about $20 for its unlimited data plan plus $10 for MobiTV usage. This carrier keeps the MobiTV name.

MobiTV worked relatively the same way on all three handsets with both carriers: two Windows Mobile devices, the Sprint PPC-6700 and Cingular 8525, and a basic cellphone, Samsung Electronics Co.’s SGH-A707 with Cingular’s 3G network. In my tests, MobiTV came pre-loaded on the devices, letting me simply select it from a list to start watching streaming content.

On the Cingular 8525, a smart phone running the Windows Mobile 5.0 operating system, I browsed through a guide until I found The Oxygen Network. The Isaac Mizrahi Show, not a favorite of mine, was just ending. It was followed by a quirky game show called “Can You Tell?”

MobiTV streams two types of programs: Live and Made for Mobile. Live shows are like those on your regular TV though slightly delayed and with different commercials in the local ad slots. I watched MSNBC’s “Hardball With Chris Matthews” using MobiTV and my regular TV, and an interview with Mia Farrow started about a minute earlier on my TV than it did on my mobile device.

Made for Mobile channels include special MobiTV content, such as music-video channels, or content for certain channels that MobiTV stitches together to show in a better format for mobile. The latter is the case with ESPN; in 15 minutes, I watched clips about football, Nascar, baseball, boxing and basketball with only a few quick commercials. In these snippets, however, lips weren’t synched with the audio.

I often opted to view content in full-screen mode, which, in 10 seconds, alters the image to take over the whole screen in horizontal view. A few times, while watching full-screen view, my on-screen content froze and had to restart in the regular view.

MobiTV says that using its service to watch programs saps battery at a rate equal to that of voice calls.

People who use digital video recorders at home to pause or rewind live TV will be disappointed to find you can’t do that with MobiTV. The company is hoping to offer these capabilities in the future. But because of the smaller screen, you probably won’t want to watch your mobile screen for as long as you would a regular TV, reducing the need to pause and rewind.

MobiTV’s services will never replace your home-entertainment center experience. But the ability to watch TV on your phone is a great way to stay plugged into news and entertainment. Just be sure that you’re using a fast network and a generously sized screen.

– Edited by Walter S. Mossberg