Backward Compatibility
The Wii is fully backward compatible with GameCube games, so all officially licensed GameCube game discs will work with the Wii. Unlike the Xbox 360 and 80GB model PlayStation 3, the Wii uses hardware-based backward compatibility, since the system contains the chipset and disc drive required to play GameCube games. This allows the Wii to play all GameCube games, whereas the Xbox 360 and PS3's software-based backward compatibility only allows them to play a few of their predecessors' games.
Setup
In order to play GameCube games on the Wii, you need a GameCube controller. You cannot use the Wii remote or Wii Classic Controller to control GameCube games. To use a GameCube controller, open the controller socket cover on the top of the Wii and connect a GameCube controller to one of the four controller ports; player 1's controller port is the one closest to the front of the console.
Insert a GameCube memory card into a memory card port if you wish to save your progress, since you cannot use the Wii's flash memory to save a GameCube game. Make sure your memory card has enough space on it to save your game. To view the contents of your memory card, click on the "Wii" icon in the lower-left of the Wii Channel menu. Click on the "Data Management" option, and then click on the "Nintendo GameCube" option. You will see your memory card's contents. To delete a file, click on it and select "Delete."
If you have gotten used to the Wii's wireless controllers and feel uncomfortable with the GameCube's wired controller, you can purchase a Nintendo WaveBird controller. The WaveBird allows you to plug a wireless signal device into the controller port and use the controller wirelessly. The WaveBird has been out of production for a while, however, and finding one may be difficult. Third-party wireless GameCube controllers, such as the Thrustmaster T-Wireless NW, may be a more inexpensive option for wireless gaming.
The Wii also supports the Nintendo GameCube/Game Boy Advance cable, which allows you to connect a Game Boy Advance to the system to access the special features of some games. Simply plug the cable into one of the Wii's controller ports to allow Game Boy Advance access.
Limitations
The Wii does not function with the Game Boy Player, which connected to the GameCube to allow users to play Game Boy games on their televisions. In additional, the Wii cannot connect to the GameCube broadband adapter, and the Wii's wireless Internet connection does not function with GameCube games. Players cannot access the online components of GameCube games such as "Phantasy Star Online."