For USD $19.99 (plus USD $6.00 shipping) you can buy, in January 2007, an adapter to use NES controllers on the Nintendo Wii from retrousb.com.
Why would you want to do that? Technically, the Wii-mote can be turned on its side for a retro "feel" and you can always go buy one of those Nintendo classic controllers but that just won't relive your past, will it?
Many of us wish we could find a good use for those old NES d-pads. You know the ones, those little bastard controllers that leave callouses in parts of your hand you didn't know a callous could grow? The only safety we have, as adults, is a limited amount of time to game.
As kids we probably spent more time indoors than our parents would permit. Some of us crawled out of our bedrooms and powered on the TV, then looked around to see if the brightness was noticed by the parents sleeping quietly in their bedroom. Like little vampires we would ball up with a blanket and slowly insert that gold Zelda cartridge and relax for a night of gaming.
Is there any other reason to use a NES controller over new fangled devices like the Wii "classic" controller? Nothing says classic like an actual classic - not a remake or a wanna-be.
Any gamer planning on doing some virtual consoling on the Wii should think about a product like this so they can truly be one with the past. When you're sitting there in front of your glowing TV at 2:00 A.M make sure you look behind you, check to make sure you've not awaken... your spouse.
source: retrousb.com