I've already read all the logitech documentation and stuff and it plugging it into the analog jack (which is in the back) only allows for 2.1 stereo sound. The analog jack in the back is like a normal green computer jack and only supports the front right and front left speakers.
I found a faq on Dolby's site
http://www.dolby.com/games/nintendo.gc.faq.html and it seems like you can have more than two speakers operating. From the sounds of things in this article, I think there can be more speakers, but I have no clue how. But I may be wrong. If it's truly only 2.1 DPLII then it kind of sucks :-/ Wish I had an Xbox optical connection or something hehe. Well, thanks for the reply and if anyone still knows more I'd be more than happy to read it :-D