Stop paying ridiculous amounts of money on that stupid Wifi adapter:
http://www.popsci.com/node/30580
After spending 2.5 hrs myself, I got it all set up with my old Linksys WRT54g Router, and it is awesome!
For anyone looking for the how-to parts of it (not as easy as the article makes it out to be) I found these sites to be super useful:
http://www.geeksaresexy.net/2007/10/...your-xbox-360/
http://www.dd-wrt.com/wiki/index.php..._Mode_Wireless
AFAIK this is all 100% legit as it is freeware and just using your own hardware, but if mods have a problem with it, go ahead and delete it.