You know, I don't think I've ever heard anybody mention whether or not the Nintendo Wii can do in game Dolby Digital 5.1 on the fly or not. I haven't heard anything about there being a optical output on the back or anything like that. I'm assuming in the year 2006 that all consoles should have this as a standard, but with Nintendo you never know. Considering the Wii is a Cube 1.5 with a gimmick controller, I'm not so sure it has the raw horsepower to do 5.1 on the fly, or if Nintendo really even thought about that. It would be a damn shame if that's the case. The GameCube had Dolby Pro-Logic II as it's best audio level, and while Pro-Logic II can almost sound like discrete audio channels, it doesn't quite do the trick. True discrete audio, is the way to go.
I've been enjoying 5.1 sound on the fly since the day the Xbox 1 was launched, and I've also been enjoying it with the Xbox 360, and finally Sony will have a system that can do 5.1 sound on the fly too. Hopefully Nintendo isn't going to have the only system that can't do 5.1 on the fly. Once you get used to that discrete sound, it's quite noticeable when you don't hear it.