This is what Scott originally posted on TMC (at http://www.teslamotorsclub.com/showthread.php/5055-New-cell-phone-app-Tesla-Tattler-works-on-all-cell-phones?p=58389&viewfull=1#post58389):

V4 (this version) runs on "off the shelf" ARM9 hardware. 

Linux ARM processor w/CAN controller, 2GB SD card, +12 pwr supply. GPRS GSM modem.

- Bennett

PS: Scott Byer (SByer on TMC) has a Tattler he hasn't installed. Might be worth a PM to him to see if he'll open it up and report back what he sees.