Not the first time this has been done, granted, but Komodo’s Retro Adapter is certainly the most elegant way of using all your old Nintendo pads on the Wii.
http://kotaku.com/234528/old-school-reunion-use-nessnes-pads-on-wii
Due to come in at around $20 when it ships in July, the Retro Adapter works like a controller hub, allowing you to use NES, SNES and N64 pads. What’s more, the hub is styled to look like an N64 (though we think it looks as much like a 3DO).
Innex Retro Adapter updates your old controllers for active Wii duty [Offworld]