We have a Wii and as far as I know there's no joystick for it The controls would be through the Wiimote, which means either you control your direction through aiming the remote where you want to go and using one of the buttons on it to move, or (more likely) you use the up, down, left, right arrow button to move and use the remote to aim. Probably rather awkward, although one would likely get used to it in short order.
IMO, the Wii is likely a poor tool for FPS games and is much better suited to other genres. It's a really fun game system, but has its limitations.
*edit* Forgot about the nunchuck. It's like a joystick, so likely that would be used for movement. If so, i can actually see that working out rather well...
Post edited February 14, 2009 by Coelocanth