All games used rumble, but no game used the speaker. When asked about it, a THQ rep told us that no documentation outlining the speaker has been received from Nintendo at this point.
Interesting that so close up until launch and a major developer hasn't been given the full details on a major component in the Wii control scheme. Check after the break for more pictures, including the Wii development kit (which is not a GameCube, like at E3).
[Update: Images pulled at the request of their copyright owner, IGN.]