Behold: The Palm Treo Pro, $549 unlocked

After a slew of leaks, the long-rumored Treo Pro finally gets official. I got a first-hand look today, and indeed, it's one slick smartphone, although you'll have to pay a pretty penny to get one.

First, let's get the basics out of the way. The Treo Pro is indeed, as expected, a Windows Mobile handset (Pro version 6.1, which includes mobile versions of Word, Excel, Outlook, and PowerPoint), and Palm plans to sell it direct, starting this fall, for—steel yourself—$549, unlocked.

The "unlocked" part means no contract, good news for anyone who doesn’t want to be stuck with a carrier for two years. The bad news? No subsidy, hence the whopping price tag.

The Treo Pro is a 3G handset, and it'll work with AT&T's HSDPA network (provided you have an AT&T SIM card). It'll also work over T-Mobile's EDGE network, but not its upcoming 3G network (wrong frequency), and because the Pro is a GSM phone, it won't work on CDMA carriers such as Sprint or Verizon. Still, the Pro's tri-band HSDPA/quad-band GSM radio means it'll work on many worldwide voice and data networks.

We'd already guessed that the Pro would come with Wi-Fi; GPS was an open question, but now it's confirmed, good news for those needing turn-by-turn directions (a 30-day trial of TeleNav's navigational software is included).

Palm's advertising the Pro as the thinnest handset it's ever sold, and it sure feels that way. Measuring just 0.53 inches deep and weighing in at 4.69 ounces, the Pro feels smaller and lighter than my iPhone 3G, and it's certainly much more svelte than older, clunkier Treos like the 750 and 755p.

As expected, the Pro's sleek design takes its cues from (and improves upon) the popular Palm Centro, and it's even a a bit slicker than the recently-released Treo 800w on Sprint. The Pro's 320 by 320-pixel display is flush with the front face of the phone, the circular Call and End buttons look great, and the X-shaped design around the central shortcut keys is certainly eye-catching. Also cool: the backlit, circular navigational pad glows when you have voicemail.

Other previously rumored—and now confirmed—features include a speedier, 400MHz processor, a two-megapixel camera, microSD memory expansion (up to 32GB—nice) and a 3.5mm headphone jack. A charger and USB cable are included in the box (a toxin-free, "sustainable" box, I'm told), and Palm is promising about five hours of talk time.

Stay tuned for my full review next week. Questions about the Pro? Leave 'em in the comments below, and I'll do my best to answer.