Okay, so what this is, is pretty much the only way to play homebrew (Indie console Games, home-coded software) on an unmodchipped Wii.
It's pretty new, and updates often. I haven't tried it yet myself, though.
I DID download it, and the file size is really small. good if you live in Australia, or some other place with limits like that. It's a save file for T.P. that you load onto an SD card from your 'puter, copy it to your Wii and override your save. (you might want to back your old save up on the SD card, if you haven't beaten it yet, though).
The Homebrew Scene for Wii is still in its infancy. But this could just about revolutionize it, for the fact you don't need to Void your warranty. or buy a Modchip. The Team working on it is also working on a Wii Homebrew Channel as well!
The only downside is, given that the Wiihomebrew scene is small, theres not much for it. There is a Linux Proof of concept, a shareware version of Quake, a few emulators, thats nearly it, sadly. Still worth checking out of you own a Wii and can borrow or own Twilight princess.
what you need:
1. an SD card thats Wii compatible. formatted as FAT16. (just FAT in XP)
2. A copy of Twilight Princess thats been ran at least once.
3. Some way to read SD cards on a computer
4. (Optional) A USBGecko (for some stuff)
instructions, Downloads, where i got it from:
http://wiibrew.org/index.php?title=Twilight_Hack
Homebrew Apps:
http://wiibrew.org/index.php?title=Homebrew_apps