It won't be announced. Wasn't last year when Miyamoto said that they didn't even had a solid concept for the new Zelda and they were just "throwing" (sorry couldn't find a better word!) ideas?
Edit: "Speaking with IGN Wii, Twilight Princess director Eiji Aonuma and Nintendo producer Shigeru Miyamoto collectively indicated that while some ideas are being tossed around for a new Wii Zelda project, nothing is very far along, or set in stone.
Asked if Twilight Princess would be Wii’s last Zelda, Aonuma said, “I can’t say, but I guess for now, maybe, yeah [laughs]. Not to say that it’s going to be the final game. There’s still a lot of potential with the Wii so there’s still a possibility that there could be another Zelda for it. We do have some ideas in the works, but I can’t say for sure because none of them have been approved and we’re still very much in the planning process, so I hope you look forward to whatever comes out.”
http://gonintendo.com/?p=21170
