Narnia was written by C S Lewis, an Oxford professor of literature. He was a Christian and is well known as perhaps the greatest Christian writer of the last century. While he wrote the Narnia series, and it does have many Christian concept in it because of his beliefs, he also wrote such well know Christian classics as 'Basic Christianity', 'Screwtape Letters', 'The Problem of Pain' and many more both of a theological nature and fiction nature.
Maybe you won't like the flick, but I did. I thought it was pretty well-done and enjoyed it. Another interesting thing is that he and J R R Tolkien, who wrote 'The Hobbit' and 'Lord of the Rings' trilogy, were both at Oxford and were close friends. One story even has it that J R R Tolkien was involve in converting C S Lewis to Christianity. The story I read had it that the two were walking together and J R R Tolkien pointed out an old tree to C S Lewis, saying that a lot of stories have been written about old trees like that and while not all the stories are true the tree exists, which is why you have the stories. Then he compared God to that tree, in that a lot of stories have been written about God and perhaps not all of them are true, but God must exists because we have all those stories.