I am crap with the internet (took me a week to set up our router originally) but I found adding the Wii phenomenally easy... perhaps it was because I never figured out how to add WEP or WPA or whatever... but it looks quite simple to input them looking at the internet settings on Wii.
It's not as if we have a special router either, it was the cheapest in PC world (£50 for a Belkin wireless-b/g)