You can locate cheats for your game either at the Gecko Codes website or through the homebrew application Accio Hacks. You can also sometimes find recent cheat codes that haven’t yet been added to Gecko’s database at the Wiired forums.
When looking for cheats you will often find multiple listings for the same game. This is because games released for different regions can have different cheats. Lists of game cheats will always include a game id, the fourth letter of which indicates the region code. “E” is for the U.S., “J” is for Japan, “P” is for Europe. “A” indicates a code will work for all regions, however, GeckoOS will not recognize game ids with the “A” code in them; you need to rename the file with the appropriate region letter. In some cases cheats will work for other regions; when I was stuck in Metroid: Other M I could only find a Japanese cheat file, but when I changed the “J” to “E” it worked.
To get cheats from the Gecko Codes website, navigate to your game title by choosing the first letter of the game and then selecting it from the list. Either click “GCT” to open the Online GCT Creator or click “txt” to download a text file that can be used offline.
To get cheats using Accio Hacks you’ll need your Wii to be connected to the Internet. At the main menu, highlight “Accio Hacks/Manage Codes” and press the A button. Navigate to the first letter of your game. You’ll see a “Channel Select” menu, where you can choose the format of the game you want (choices include Wii, WiiWare, VC Arcade, Wii Channels, GameCube, etc.). Highlight the channel you want and press A. Now choose the first letter of the game you are looking for and press A. Highlight “Accio Hacks” and press A. After the file is downloaded you will be returned to the game list. Press the B button to back out. You will now see your game’s cheat file listed. Highlight it and press A.