In a PDA/phone universe dominated by Palm and Windows Mobile devices, the Sidekick (made by a company called Danger, but marketed exclusively by T-Mobile) has always been a maverick with a devoted, if small, following. To its predecessor's repertoire of features (phone, Web browser, e-mail manager, and camera), the new Sidekick 3 adds a faster processor, support for a faster data network, a music player, and other goodies that should please the faithful and draw new converts who don't require a well-established software platform from their connected handheld.

I tried a shipping version of the device, which costs $300 with a two-year T-Mobile contract (as of 7/7/06). T-Mobile charges a very reasonable $20 per month for unlimited data services if you also get a voice plan; the cost is $30 per month if you want to use the Sidekick 3 only for data.

The notion of data-only use is not far-fetched, because the Sidekick 3 has some shortcomings as a phone. While it's a tad thinner than the previous version, its dimensions--5.1 by 2.3 by 0.9 inches--and its 6.7-ounce weight are still a bit bulky, even for a hybrid. Also, to dial a number you must first swivel and flip up its display (with a roomy 2.6-inch screen) to reveal a QWERTY keyboard on which you tap out the digits. Pressing a button sporting a traditional green phone icon (located to the right of the display) initiates the call, but you must then flip the screen shut to talk into the device. All that flipping is at the very least distracting. Fortunately, you can call address-book contacts without having to use the keyboard, and you can use the included earbud stereo headphones instead of holding the handset to your face. Voice quality in my test calls was quite good.

Images captured with the Sidekick 3's 1.3-megapixel camera were better than those I've snapped with other phone cameras, but still on the fuzzy side. The new music player plays MP3 files only; audio quality wasn't great over the external speaker, but was quite good through the headphones. One of the Sidekick 3's most likable qualities is the ease with which it transfers music and photos to and from an included 64MB miniSD Card to a PC. There are no drivers to install: You simply connect the device to an available USB port using the included USB 1.1 cable, and the PC recognizes the miniSD Card as an external drive.

And while you get no desktop software, T-Mobile does provide a Web-accessible desktop that automatically syncs, over the air, your Sidekick address book, calendar, to-do lists, e-mail (from your T-Mobile-provided account and/or up to three additional POP/IMAP accounts), and all photos saved to the device's memory (as opposed to the miniSD Card). It's a pleasant change from phones that make photo transfers difficult and--if you don't have unlimited data service--expensive.

But the Sidekick 3 really shines in e-mail, text messaging, and instant messaging, thanks to a happy combination of sensible and intuitive user interface design and one of the best keyboards I've encountered on a handheld. Web browsing is also a strength: Ads are stripped out by a proxy server, and while the browser doesn't preserve the look of sites, the content is generally very readable, which isn't always the case with handhelds.

The Sidekick 3's other upgrades include a small but smooth-running trackball for easy navigation between fields and menu options; a removable rechargeable lithium ion battery that ran for a very respectable 9 hours in our voice-call test; and support for T-Mobile's EDGE network for data speeds on a par with those of very good dial-up.

The Sidekick 3 isn't perfect. Its display, even when set to full brightness with the backlight on, isn't as brightly attractive as those on competitors such as Palm's Treo units or most Windows Mobile PDAs. Its biggest drawback, however, is the dearth of third-party applications for the Danger OS on which the Sidekick is based. Palm and Windows Mobile users can choose from thousands of applications--games, productivity software, utilities--available from a variety of Web sites; Sidekick owners have several dozen (accessible as over-the-air downloads via a Sidekick icon).

If the versatility that third-party apps afford and a petite shape aren't priorities for you, the Sidekick 3 is a good connected handheld for e-mail, messaging, and Web browsing. Heavy phone users might prefer a device with more straightforward dialing options; but for anything involving typing, the Sidekick is hard to beat.

-- Yardena Arar