Another alternative is to try an eDive. Its PC based and free at www.ediving.us. The dive sites are real, mostly SoCal for now, but we will be adding more. Right now there is a $10,000 contest going on. You also check out ’videos’ of some recent dives at http://www.youtube.com/edivingus
Honestly, the graphics blow the Wii away...but you need a pretty high-end computer.