This is what I've been talking about. For all those of us with wireless enabled laptops and a wired ethernet connection hooked up, this could be the way to set the laptop as a wirless access point for the wii to connect to the internet through.
I followed all the directions and got the wii to recognize the ad-hoc network that i created but it ultimately failed the connection test. Here is the site with detailed instructions on how to do this: http://www.hardwaresecrets.com/article/418/3
If anyone can figure out how to get this working succesfully. It could mean that many of us with wireless enabled laptops and an internet connection can skip buying the $40 wifi adapter.
I'm sure it can be done fairly easily. I do the opposite with my Xbox 360. I have a wireless connection and instead of giving Microsoft (sucks) $100 for a wireless adapter I just run an ethernet cable from my wireless Mac to my 360.