http://www.walden.com/walden/properties/caspian/

That's the link to Walden Media, where you can view the trailer. The release date seems to be May 16th, 2008.

I just joined up to browse their forums, and boy were there some heated opinions about Susan Cooper's The Dark Is Rising, which apparently was botched badly when they turned it into the movie The Seeker. So glad I didn't pay to see that one yet ... the book is great. Let's hope the quality of Prince Caspian is at least equal to that of The Lion, the Witch, and the Wardrobe!