The Twilight Hack is described at Code Retard.
It works by using a bug in Zelda - Twilight Princess. In short is goes like this:
- get WAD Installer 2.1 and copy the
wad-installer.elf to the root directory of your SD-card and name it
- get the Twilight Hack Beta (for
the Wii 3.3 firmware) and copy the
/private/wii/title/RZDP (P for PAL).
- copy all wanted games (
*.wad-files) to a directory
/wad on your SD card (4MiB ~ 59 blocks)
- get Zelda - Twilight Princess, run it at least once on your Wii to create the savegame slot
- insert SD card, delete savegame on your Wii and copy the Twilight Hack savegame from your SD card
- now run Zelda, load game, walk towards the guy and talk to him
- the screen goes black and shows the WAD Installer which installs all files found in