Instructions
Insert your SDHC card into your computer.
Download the Homebrew channel and Gecko OS 1.07b onto your SDHC card. For both programs, right-click and choose "Save As" and select your SDHC card as the destination.
Go to the Gecko Codes website and download the Item Modifier cheat for "Mario Kart Wii." Choose the "M" category on the left-hand side of the database page. This will take you to all the Nintendo titles with an "M" title. Select "Mario Kart Wii." Highlight the entire text, right-click and select "Cut." Open Microsoft Word or a text file and right click the document and select "paste." Save the text document as "Mario Kart Wii.txt."
Find the APPS folder in your SDHC card. Double click the folder and find program "Codemgr.exe." Double-click the "Codemgr.exe" file to open the Ocarina Code Manager. Go to "File," scroll down to "Open," and choose the "Mario Kart Wii.txt" text document you saved from step 3.
Select the Infinite Item Modifier cheat from the list generated by the Ocarina Code Manager and the "Mario Kart Wii.txt" text document. Click on "Export to CGT" in the bottom-right corner of the screen. A message will appear asking you where you want to store your file. Select your SDHC card and hit the "Store" button.
Eject your SDHC card from your computer and insert it into your Nintendo Wii console. Open the Homebrew Channel download and boot up Ocarina.
Insert your "Mario Kart Wii" game disc. Begin play and enjoy your infinite item cheat.