What are the similarities and differences in the hobbit on hobbit movie?

Since the release date for the first Hobbit film is still over a year away, there's no way to know what differences might exist between the book and the film.

However, we do know that the characters of Saruman and Galadriel will appear in the film(s), even though they do not directly play a role in the book. This suggests that we may see the meeting of the White Council, where the lords of Middle Earth gather to discuss the growing power of the "Necromancer" (later revealed to be Sauron). In the book, this takes place after Gandalf leaves Bilbo and the dwarves as they are about to enter Mirkwood.

Based upon statements made by Peter Jackson (and by Guillermo del Toro when he was still attached to the project), the producers would like to tie together the events of The Hobbit and LOTR as neatly as possible, using whatever background information is available in each work. However, they have stressed that they do not have rights to use information from The Silmarillion or Unfinished Tales.