It’s official — they’re going to start filming on March 21st. Peter Jackson is at the helm again, with official sign-on by Christopher Lee as Saruman, Ian McKellan as Gandalf, Andy Serkis as Gollum, Cate Blanchett as Galadriel, Sylvester “Seventh Doctor” McCoy as Radagast, and Elijah Wood in a Frodo cameo. No word on Elrond, as far as I know, but also rumors (unconfirmed last I heard) of Orlando Bloom returning as Legolas.
The presence of Saruman, Galadriel, etc., is part of the whole “expanding on the storyline” plan, to flesh out the story by including the White Council’s ousting of “The Necromancer” from Dol Guldur in Mirkwood, which is hinted about in The Hobbit (mainly as the “business to the south” that Gandalf keeps disappearing to through so much of the book to take care of). Legolas’ presence is presumably a side-effect of the dwarves being the prisoner of Thranduil, Legolas’ father — it wouldn’t take much stretching for him to be one of the wood-elves who have the most face-time. (Maybe Bilbo had a little more inside help than he thought there, eh?)
Release date of December 2012. Yeah, baby! It’s about time!