Don't be a twat and dig up old threads. This has been beaten to death here. The wireless chipset in the Wii is g capable, but the current driver doesn't work right. I'm sure N will get the kinks worked out eventually, but for now, mixed-mode is required. Go read up on N's support site and see for yourself.
Edit : I did reply to this comment, but then retracted it. If you can't speak with a civil tongue, don't bother.