Copy and Paste from gscentral boards:
Credit to original poster Hells Guardian
Default Using The Action Replay GCN on the Wii Without a disk or AR Card!!!!
Someone has managed to get this all working. this is an app that will launch The GCN AR dol and then force load the Gamecube game with the codes in place. It will give you complete access to the uses and functions of the Gamecube Action replay.
Things you will need.
1. The Homebrew Channel installed on your wii.
2. An SD card for use with the wii homebrew channel.
3. At least one 3rd Party Gamecube Memory card. Two is best.
4. A way to copy the action replay save data to you Gamecube memory card in slot B (a homebrew app for the wii to do this is included however it wouldn't work for me.......) You may be able to just use the actual Action Replay card instead. I couldn't try that.... I don't have one.
5. A Gamecube controller. (Duh)
6. A gamecube Game.
7. The download linked to at this location.
http://www.megaupload.com/?d=XWRCAU7S
When you have all these things just do the following
First take the Rvl-mios-v5.wad.out.wad file and the ar114.dol and apps folder and place them in your front sd card root dir. If an apps directory already exists on your sd card then copy only the subfolders into the apps directory. Now from the Homebrew channel run the program Mios patch. This will patch your Mios to enable the loader and the homebrew loader for the gamecube as well. Just follow the onscreen instructions. (shouldn't cause any problems for any of your wii's GC Compatability)
Insert original Gamecube game then run the Action Replay Loader from the Homebrew Channel. It will load into Action Replay v1.14. You can now use cheats with your ORIGINAL Gamecube dvds. (Do not try to change which game you are using after you start the AR. I have yet to try it with a multi disk game so I can't say if it works or not.......)
I'll be uploading a Wad File at a later time that will install a channel directly to your system menu to load this.
This does work but often has compatability issues with certain memory Cards (official Nintendo brands do NOT work). If yours do not work I don't know what to tell ya........ Best of luck to everyone with this. I'm uploading a channel for it as I type. You will still have to have the other items on the SD card. this is just the loader that will launch the dol file for the AR.
Here is the Channel
http://www.megaupload.com/?d=C53IR24A
You may want to start by taking a look at the memory card you are using, hope this helps!