I remember reading these books when I was a child and was so very pleased when the first movie came out about the first book in the series written by C.S.Lewis. Then when the second movie came out, I had to hurry up and buy the collector's edition of it as well (and it is a good thing I ordered it online because it flew off of the shelves). The books in the series are as follows:

The seven books
1.1 The Lion, the Witch and the Wardrobe (1950)
1.2 Prince Caspian: The Return to Narnia (1951)
1.3 The Voyage of the Dawn Treader (1952)
1.4 The Silver Chair (1953)
1.5 The Horse and His Boy (1954)
1.6 The Magician's Nephew (1955)
1.7 The Last Battle (1956)

yeah the magician's nephew though is supposed to be the first book but it was only written later.
Yeah I think another film is coming out soon

The silver chair is the next film to come, it'll be released in winter 2010. As far as I know they've just finished the filming and now they start with post-production.
The Magician's Nephew is actually the prequel to The Lion, the Witch and the Wardrobe, though it was written 5 years later.

The Silver Chair?? No. The latest Narnia movie is The Voyage of the Dawn Treader. Where have you people been??