Narnia C. Lewis said that Aslan did not "represent" Christ. The way he explained it to one child was to imagine that there was a place called Narnia and in it, Christ appeared in the form of a Lion. Aslan IS Christ as he appears in Narnia
The book was dedicated to C.S Lewis' niece, I think, Lucy. The dedication said something like this "I started this book when you were young enough to read fairy tales, but someday you will be old enough to start reading fairy tales again.