"wii swiss booter" will do the job for you. no need for an action replay.
That won't work very well if he's doing this on a GameCube. Didn't you notice that he posted this thread in the GameCube section?
Does the New Action Replay for the Gamecube without the Memory Card, Let you use it as a SD Launcher?
Does your AR still let you create new game entries and input in new codes? If it does, then yes. But you'll need to provide a memory card of some kind on slot-b otherwise you will find yourself inputting the codes on every start-up.

( I happen to have v1.14 of AR and it won't even start if I don't have a memory card in SLOT-B)
I don't remember if AR will create a new file on slot-B if you don't have the original memory card that came with it. I assume newer versions that don't include the memory card just expect you to provide your own on slot-B. I don't have a second card to backup my AR file on, so I'm not exactly willing to test that theory.
As far as I can tell, the only thing that would prevent AR from launching stuff from SD, is if you got the version that doesn't allow you to input new codes/games. I don't know which version started disallowing that. But it's easy to check. Just boot it up and see if you can add new games/codes.
If not, then your SOL and will need to either find a version that does or just buy the SD Media Launcher which would be harder to find then an Action Replay. (for cheap anyway, the Datel website still sells it, but the shipping is expensive)