sur le site de wii save ... -> instructions:
Wii Save - How to Share / Use Wii Game Saves
How do I use someone else's save?
After downloading a save, you'll either get a plain old data.bin or a zipped file.
If you have a data.bin, you have to place it in a folder structure on your SD card like so: \private\wii\title\GAME\data.bin (replacing GAME with it's corresponding game code from the game code list).
If you get a zipped file, it most likely has all of it's folder structure in tact, so all you have to do is extract it to your SD card so it shows up like the above folder structure.
Once you have the file in place on your SD card, you can then put the SD card in to your Wii and go to your saved game(s) on your SD card (Wii Options > Data Management > Save Data > Wii > SD card tab), select the saved game that you want and select Copy. Keep in mind that if you already have a save on your Wii that you're trying to replace, it wont overwrite it, so you'll have to backup your save, then delete it off your Wii internal memory to be able to transfer the new one on.