Today, Samsung bowed the Jack, another sequel to its popular BlackJack line of Windows Mobile smartphones on the AT&T network. Samsung changes up the keyboard, but keeps many other specs on par with previous BlackJacks. The new Jack's best feature? It can be upgraded to Windows Mobile 6.5.The Jack is another mono-block shaped smartphone from Samsung that takes the appeal of the previous BlackJacks a step further with a somewhat more attractive design (picture here). The keyboard appears to have been completely redesigned, and, dare I say, it looks much more usable than keyboards on previous BlackJacks. If you look at the picture, you can see dedicated shortcut keys to apps sich as the camera, Internet, GPS, and email.

Other specs include access to AT&T's 3G network, a 3.2 megapixel camera with video capture, GPS, Bluetooth, Wi-Fi and all that Exchange-compatibility that Windows Mobile is known for.

It runs Windows Mobile 6.1 Smartphone edition, which is the non-touch version of WinMo. Samsung said that the Jack will also be upgradable to Windows Mobile 6.5. WinMo 6.5 isn't due out until later this year.

One nice feature called out in the press release is threaded messaging. Threaded messaging has become a must-have feature in my book, as it helps organize conversations in a much more user-friendly manner.

The Jack goes on sale May 19, and will set you back $99.99 after a $100 mail-in rebate with a new two-year agreement.