Where do you connect the microphone to the Wii?

Wii speak accessory-

If you own rock band for the wii and have the "wireless adapter" in, take it out, that's the same spot that the wii speak accessory needs to be plugged into.

If not, the correct plug-in is the one on the very top-left corner (when looking directly at the back)

Rockband micrphone-

This accessory must be plugged into the first or second slot of the rock band "wireless adapter"