At work today they had a demonstration unit of the Wii. During my lunch hour I tried it out.
The software that was in the system was Wii Sports. Apparently this software features a few different "party" games like Tennis, Baseball, Golf, Bowling and Boxing all in the same package
When I played it the boxing game was loaded. This game used two controller "pieces" that are connected together with a wire. These controllers are wireless I held a controller in each of my hands. I was playing is a versus mode of the game where the screen was split for each player view.
Playing the game: Each controller was represented by each hands movement. No buttons are needed for game play. Where as I had to physically move each hand and arm to have my character represent that movement.
Tips: Bring the controllers close together to block a punch. and lean to one side to Dodge a punch. You can make punches to the head area by "punching" higher in the air, where as a "punch" made in the mid area will get the gut on you opponent .
To make a roundhouse punch (a good powerful punch) ,instead of moving your arm straight out, swing your arm in an arcing motion to the side.
My final reaction, this will be a fun system. But your arms will get really tried after a lot of game play.