At Shigeru Miyamoto's Developer Round Table during E3, Shigeru mentioned that he wanted to announce the next Zelda title for Wii, however he changed his mind and wanted to wait till TGS later this year when he had some more solid information.
He did however bring a piece of artwork to show, and that has finally been released.
http://img40.imageshack.us/img40/5430/fullzelda.jpg