My Wii had been functioning fine (connecting to an Airport Express) for several weeks until we suffered a power outage (What can I say, the Wii isn’t on the UPS!).  After bring the entertainment center back up (it’s like mission control at NASA), the Wii would not reconnect to the wireless network at all.  Repeated attempts to enter the password as well as altering several aspects of the router configuration failed to help.

There was however one action that allowed the Wii to connect.  Changing the channel that the router operates on from “Automatic” to Channel 1 allowed the Wii to see the world again.  Someone at Nintendo needs to put out an update to allow their hardware to connect on more that two channels (I’ve heard that Channel 11 also works quite well).