Well apparently The Voyage of the Dawn Treader has an official release date now. December 10th, 2010. Narniaweb has more info here.
I have to laugh at the quote about Fox and Walden deciding that Narnia is a winter franchise. That's pretty much what the fans have been saying forever - since before Prince Caspian came out.
I think it's sad that things go so messed up, but at the same time I'm interested to see Georgie Henley and Skander Keynes play an older Lucy and Edmund than they would if filming had begun last fall as planned.
So we'll see how this franchise pans out. It's certainly been pretty rocky so far.