Medal of Honour is a game where you play a soldier in World War II. EA created a special version for the Nintendo Wii (and the Nunchuk) and provided some animations of how you gesture to play.
Tutorial on jumping and crouching
How to jump and crouch. (source)

Here are tutorials on turning around, throwing a grenade, reloading your gun, using your bajonet, and the best one of the lot: steering your parachute.

Update June 11, 2007: Here is an impression that is a bit more realistic: