The Centro is back, this time for AT-T Wireless. We reviewed the Centro on Sprint's network last Fall and now AT-T is offering the GSM version for the same low $99. This makes the Centro the most affordable touch screen PDA phone on AT-T's network, and like Sprint, they're hoping that first time smartphone buyers will be attracted by the price and hop looks. The Centro runs Palm OS and it has a QWERTY keyboard that's ready for texting and email, including push email. It has a 320 x 320 color display, Bluetooth, a 312MHz processor and a microSD card slot.