Ocarina is the stand-alone code handler
Download it here:
Ocarina is a very simple Wii application for your homebrew channel. What it does? Start a game.. but there's a twist of course.
Ocarina checks the GAME ID.. like RZDP01 for Zelda Twilight Princess (PAL). Then it checks the inserted SD card whether it can find a cheat code file for that game: in this case it would have to be name [sd]:\codes\rzdp01.gct
Quoted from: Link
Ocarina - SD WiiRD Cheat Playback © Link
All cheats in this video were not created by me.
All Footage was recorded by me, and all characters controlled in the video were controlled by me except the Wi-Fi matches and the 3 Ike's vs. Pit.