Narnia III: The Voyage of the Dawn Treader
With Chronicles of Narnia: The Lion, The Witch & The Wardrobe being a success it wasn’t a big surprise they where going to make a second movie.
The second movie isn’t even ready yet and talks about a third one are already going on. Neil Burger, the director of “The Illusionist”, seems to be attached to the third movie.
If rumors are correct the movie will be “The Voyage of the Dawn Treader”, the third (and the fifth in chronological order) Narnia book written by C.S Lewis (source MovieHole.com)