Location
Wii codes are found on the back of cards purchased at electronic, toy and department stores. You must scratch the back of the card to expose the Wii Code. Be sure to scratch the area lightly with a coin, not a key. You do not want to scratch the code off the card because if you cannot read the code you will not be able to enter it online. You also cannot refund the card for a new one through Nintendo or the store you purchased it.
Use
You can use Wii codes to purchase games, avatars and accessories for games. This is done through the Wii Store online. Enter the codes through the Wii store on the Wii main menu. You can browse the store and preview games with demos or purchase full-length games. You must create an account with your card and be logged in to make purchases.
Other Codes
At times Wii codes may also refer to cheat codes. Cheat codes are found in strategy guides or online. These codes allow you access to features of games that are unavailable other wise. For example, certain codes may give your character certain extra powers earlier in the game or allow you to skip levels. This type of code will vary from game to game and must be entered from the main menu.
Online
Wii cheat codes are not officially released for games. Most codes can be found on Wii cheat code websites or Nintendo fan message boards. Often gaming experts or game fans will release codes they find work to unlock different features of games.