Just a couple of days ago Nintendo introduced the Wii RemotePlus add on that helps better mimic your hand motions now they have a microphone add on that provides more interaction. The WiiSpeak microphone is add on device that allows you to interact with certain games and also allows you to chat with fellow Wii gamers.
The WiiSpeak is still being thoroughly tested but rest assure, Nintendo will test it to work perfectly. The first game that will utilize this new hardware will be "Animal Crossing" that comes out later this year.