To be specific, I'm talking about the ScoreHero Invades Neversoft topic on the forums in that site. Here's a bit of a sit-rep (albeit not very detailed):
Legends of Rock (aka Guitar Hero 3) kicked Pandora off the list of playable characters. Now they have some Japanese Pop-influenced character, Slash of Guns n' Roses fame, and a couple of other "Rock Legends". They even tossed in a high-speed Dragonforce song that most of the Guitar Hero players on that site have been waiting for all year: Through the Fire and Flames, which is, apparently. Jordan and Misirlou mixed together into speed metal.
By the way...
Jon, please add GH to the spellchecker.