This movie is amazing. You should all go see it. It stays very true to the book, but that doesn't make it boring. I thought it was extremely well done.
The first few scenes are wonderful. Whoever the director was, did a great job depicting the Battle in the Skies over London, and I feel that he captured the emotions of the children's evacuation. This is a part of the book that present day readers, especially American readers, miss. The kids were not on a summer holiday in the country when they found the wardrobe - they were escaping Nazi bombings. One of Susan's (or maybe Peter's?) later lines brings this into especial focus...anyway, go see the movie. It's wonderful, and well worth the 8 bucks.
On a semi-unrelated note, Serenity the movie is not as good as the TV series. I'm glad I have it - it's a good movie, but it's nowhere near as good as the show. I'm not going to ruin it for anyone, just commiserate with Firefly fans who saw the movie as well...too bad. But go out and buy it anyway - I want more Firefly.