The Harmonix community manager writes at the official Rock Band forums that a routine patch for the PlayStation 3 version of the game is coming soon, one that will address "a number of items related to guitar controller compatibility." The patch was expected to be released yesterday, but unspecified circumstances have delayed the software update. While not officially confirmed, it's assumed that this is in reference to adding support for Guitar Hero III Les Paul controllers. Good news for PS3 Rock Band owners who are sorely in need of a bassist, bad news for those who bought the PlayStation 2 version of Guitar Hero III because they didn't see the point in buying another guitar controller. I am, of course, referring to myself, and regretting my lack of foresight on the matter.
PS3 Controller Compatibility Routine Patch [Rock Band Forums]