Word is that the film will include the story of The White Council's battle with The Necromancer (who turned out to be Sauron) at Dol Goldur in Mirkwood.

The White Council was made up of Saruman (before he turned all evil and junk) Gandalf, Elrond, Galadriel, and Cirdan (bearer of the ring of fire and the guy whose ship bore Frodo and Bilbo away from the Grey Havens at the end of ROTK.) It's possible that other members may have included Radagast the Brown, elf warrior Glorfindel (whose role in the film trilogy was taken up by Arwen - in the book it was him who saved Frodo from the Ringwraiths, after Frodo was stabbed by the Morgul blade) Legolas' father, Thranduil, and Galadriel's husband, Celeborn.