Not endorsed or made by Nintendo mind you, but this is one of the safest ways to 'hack' your Nintendo Wii WITHOUT modifying it to play homebrew applications (read: play NES games) such as Emulators, alternative OS's (still in testing) and other apps being 'brewed'. 

http://wiibrew.org/index.php?title=Twilight_Hack

Also check out http://wiibrew.org/index.php?title=Homebrew_apps to see what homebrew is currently available.

I finally got the NES emu able to read the roms directory...framrates are exactly like the original NES, sound emulation needs a little work though.  Beats paying for each VC channel from the big N.  I can't wait until future better versions of some of these emu's come out.

Damn, I still need to get my WiiKy working... My hands have become too unsteady for a good solder joint. QQ

I could do it for you if you'd like.  I have a precision solder station at work.