Ahhh okies, I shall be doing that nexttime I've got the Wii on. My wi-fi is through a Nintendo USB connector (unless I'm at my mum and dad's) and thus is crappy at best.
http://risingdragon.livejournal.com/126843.html#cutid1 <--- This is a tutorial written by a guy on LJ, he explains how to get on wi-fi including how to bypass security (I think)