I would seriously think about avoiding the usage of an IR laser, unless you have a specific need for it, and know that there will be no humans or animals around. The reason being is that since the eye cannot see IR wavelengths, but can still be damaged by them, you won't blink if you happen to have it shining in your eye until the damage is so great that it is too late. It is better to use a visible laser (keep it under 5 mw) if usage will be around people or animals, as it will provoke a blink/avoidance response should the laser inadvertently shine in their eyes.
[edit]Using the wii camera sounds interesting though; if you could place four laser dots and scan them around - you could potentially do the multi-point scanning system. BTW - don't worry about IR vs visible red; it should still pick it up unless it has filters in the camera, in which case you may want to give thought to what I said, unless you don't give a whit about your's or anyone else's vision...[/edit]