Things You'll Need
Instructions
Purchase a Guitar Hero peripheral converter. These peripherals are widely available at game specialty stores or at online electronics retailers.
Plug the PlayStation 2 peripheral into the long end of the converter. Then plug the USB end into one the PlayStation 3's USB ports on the front of the console.
Power on the PlayStation 3 and insert the "Guitar Hero" disc. The game will recognize your peripherals as compatible, and you can play the game as you would on a PlayStation 2.