Is there any way to play Guitar Hero 3 downloadable content with GH3 (PS2) on the PS3?
In short, there’s probably not a legal way for you to do this. Guitar Hero 3 for the PS2 isn’t built for downloadable content, and it surely won’t recognize the tracks you have downloaded from the PS3 store. If you look on sites like ScoreHero.com, though, you can see people creating custom content for Guitar Hero 2 & 3 on the PS2. You will need a DVD burner and a way to play backup PS2 games on your console, which is difficult and risky on the PS3. Dubious torrent sites have links to game discs that have the DLC that I won’t link to here. Your cheapest and best bet would be to invest in the PS3 version of the game. If you have the Ant Commandos universal adapter, you might not even have to invest in the guitar version.