If you are using a linksys router, and are experiencing frequent disconnections or are unable to battle in wifi at all, I have discovered the solution to this problem. It will require alot of manual setup for the router and the Wii, including port forwarding the Wii, obtaining a static IP address, changing the channel of your router and downloading the most recent firmware for your router.

Anyway, there is a link I could supply however there are forums there so I cannot. Please PM me if you wish and I will help you to the best of my ability. I was having problems and was pretty angry until I did all this, now my Wii is much smoother on the internet.