I really liked the book. It gave a lot of insight into those charachters. I think Stephanie wrote it for the writers of the movie, because you get a small taste of what she wrote about in eclipse (the movie). It's interesting to see how the other half live, since the Cullens aren't exactly normal vampires. Amazon and e-bay have it for pretty cheap.
What did you think about Breaking Dawn. I'm reading it again right now. When I read it the first time I did it over 3 or 4 days and I LOVED the first half or so, but started to get confused by all the new charachters she introduced.