We first told you about the Samsung Epix earlier this month, and today AT&T Mobility made it official.  The new Windows Mobile 6.1 Professional Smartphone is now shipping for $99 with a 2-year service agreement and a mail-in rebate.

Aside from UMTS/HSDPA 3G mobile broadband, aGPS, Wi-Fi, Bluetooth and a microSDHC card slot, the Epix also features an optical navigational interface which works like the trackpad on a notebook PC.  The Epix is the only smartphone sold in the U.S. with this type of system navigation.

The Samsung Epix is available today at the AT&T Mobility Web Store with limited availability at AT&T retail stores.