Fina-fuckin-ly. Over at the Guitar Hero forums, Acitvision has finally posted a to-the-point compatibility chart for which instruments work with which game. After their complete asinine excuse for refusing to allow interoperability between GHIII and Rock Band peripherals, I'm glad they finally came to their senses. I'm only posting the Xbox 360 and PS3 chart here, because seriously if you're playing either of these games on Wii you should be beat with a cleat. If you really need the PS2 and Wii chart hit the link above. Gays. Not that there's anything wrong with that.
Just in time for the holidays.