Wii controller nunchuck adaptors
 

Don't forget that if you already have Nintendo Wii nunchucks and you don't want to get rid of them, use a "wireless nunchuk adaptor".
 

The nunchuk adaptor consists of 2 parts, one takes your plug and the wiring from your nunchuck and the other attaches to the base of your Wii Controller. (back to wireless nunchucks)

They are cheaper and mean that you can use your existing Wii controller nunchucks, here are just some of the better wireless adaptors ;

Click on the images for more information.