What I really think is that the nintendo revolution has wireless compatibility but it will hook up with wired broadband. Then since the DS is wireless the DS will be able to get online because of the revolution. In this way the revolution is the online router to the DS and people won't have to spend money to upgrade there network for either system. Also from what I’ve heard the online system nintendo's planning on having will be sort of like xbox live. It will feature forums, chat rooms, a buddy list, and a online magazine exclusive to the NR. The magazine will be kinda like the nintendo power just online. There will also be demos and game previews. You will also be able to talk to your friends who are on either the DS or the NR this way if your friends on the ds you could ask him to play such-and-such game on the NR.
I really think that the revolution will be some sort of wifi router or at least support wireless devices such as the ds at least connecting to the revolution. I think this because I have heard that the controller is going to be wireless and if this ends up being true then it would be really easy for the Nr and the DS to link up.