Interesting! Your bigger display and Atmega644 remind me about these german projects (full documentation and videos inside):
-> S65-Shield for Arduino (display is taken from S65 - popular GSM phone by Siemens)
S65-Shield - watterott.net
-> ATM based web radio with "big" display
AVR WebRadio - watterott.net
PS if possible pls. share more details about your board