I just got back from seeing Eragon, though I read the book first.
The book isn't bad, its just geared for a younger audience. Its still pretty decent though.
Warning *SPOILERS!*
The movie was disappointing, at first it appeared to follow the book . . . for about the first 15 minutes. Then it started skipping things, important things. Almost all of Eragon's travels with Brom were removed, almost all of Eragon's travels with Murtagh were removed. Arya seems to be human, I didn't see any dwarves. Solenbum, the werecat, was removed. Angela the witch had a short scene where she reads Eragon's fortune, but she doesn't journey to the Varden like in the book. Some of the special effects were pretty good, especially with Saphira and her battle scenes though.
*End Spoilers*
I haven't read the second book yet, I've heard mixed things about it. Since I've got a stack of other books to read, I think I'll hold off on it until its in paperback and the 3rd book is out.