Oh, I thought you knew how... :p
Anyway there are various programs from the internet, one of them being the Savegame Manager, which I use.
You require Wi-Fi & a flashcart to use it, and maybe that SmallFTP program too.
BTW how about VM'ing me instead? I think I didn't check the "Only Friends, Mods, & Admins can VM me" checkbox from the options...