The Wifi solution used on the Wii has a SiGe Semiconductor 2521A60 front-end (actually dealing with Wifi signals) and a Broadcom BCM4318E basecard which deals with buffering packets of data in and of the main Wii system as well as dealing with secure communications. The datasheet for the latter is here on datasheetpro. I'm still looking for the exact pinout, but it's safe to assume that the basechip controls the front-end and when it's inactive, the front-end will use less power & not be CSed...
I've E-mailed a friend at Intelligent Systems to see if they know. I want to make a 1 Gamepak/Disc game that will spread through Wifi or USB to upto 16 players at once. If you DON'T have the pak/disk however, no level design or game-club membership.