"Rock Band"for xbox 360 and PS3

The game Rock Band is suppose to come out this holiday. Rock band the game will have a voicalist,lead guitar,bass,and drums. Harmonix said "we will not use the covered versons of the songs like off the game guitar hero". For this game you will be able to play co-op online and play battle of the bands(it's what they say).So if your friend is late or just doesn't come you guys can just play online.