Ok get a game started and you will see the team VS team thing. Grab your controllers (wii motes) and move them to their respective teams. You may have to press a button on the Wii mote to turn it on.
Before you go online with it you should practice your jump shot and other skills because those guys are good.
Oyeah 4 people can play you just need extra Wii motes and nunchucks. The jump shot thing is sweet because if you do it right it works just like a real jump shot! I'm sure there will be more game out that make even better use of this system.