So it was announced a few days back, but there's been relatively little info so far. I followed a shiny link on the Escapist, however, and stumbled across these scans of the Game Informer article on Portal 2. There's some mild spoilers and snippets of dialogue, but also a lot of detail on new gameplay elements.
Affects me very little (would have preferred an Episode 3 tie-in surprise, of course), but Portal 2 releasing on the PS3 with Steamworks support isn't exactly a bad thing.