The whole story is, are we sitting comfortably?, Sony has removed the PS2 chip from the PS3, but the system can emulate, on day of release, approx 1000 PS2 games, and with regular firmware updates(assuming you're connecting the PS3 to the net), the number will grow and grow, so eventually(assuming(again) guitar hero won't be in the original 1000) you will be able to play the game on the PS3, but as i've said before, as long as the connection from the guitars is a USB and not the same as the regular controllers, you should be alright.