It's really odd, I cannot connect to my linksys router with my Wii OR DS, yet I can with my PC, 360, PS3, and PSP.
I strongly assume that the issue I'm having has more to do with Nintendo Wi-fi, if anything? I was able to randomly connect to my router on one test, yet when I try again and again, it's having mixed reactions. Sometimes it works, others it doesn't even detect it.
So, what would you say it is? A router issue, or more in hands of Nintendo Wi-fi? Looking at their support board, there are a large number of topics about people no longer being able to connect online, so my personal guess is that.
All I wanted to do was play some Brawl because I wanted a break from Metal Gear Online. Guess I have no choice but to play some more MGO :P