From my Librarything Review:
Coraline is an awesome book about a girl who goes through a door to another world. She meets a monster that pretends to be her other mother, but who wants to keep Coraline there forever and replace her eyes with buttons.
I think the author's intent is to encourage bravery because Coraline talks to herself about bravery. Coraline shows bravery by throwing a cat at a monster and sticking her hand into a spider web.
Another author's intent may be to tell readers to be happy with the family that they have because at least it's better than having monsters as a family.
I highly recommend this book to Goth people and people who like scary books. I usually don't like scary books but I liked this one because it was suspenseful.
About the Coraline Movie:
In the movie, Coraline gets a doll from Whybe, a friend, that really belongs to her other mother. The other mother is using the doll to watch Coraline. This is different from the book, because there is no Whybe and no doll in the book.
Even though the movie was different from the book, I liked it because it was in 3D. The 3D made it look like everything was popping out at you. I also liked the soundtrack because it was creepy.
I recommend reading the book before watching the movie, but I don't think it really matter. Neither one spoils the story for the other.
Here are some Coraline Links:
Cornered In a Parallel World - New York Times Review of the movie. Click on the link for Creating an Other World to see how they made this 3D movie.