I don't really have experience in this, but I think I'll be able to help you out since I plan to do the same thing to my Wii once I have everything I need in place.
Here's the site which contains guides and other things related to Config USB Loader.
WBFS Manager, which you'll need in order to be able to convert ISO's to the necessary format to be playable on the Wii through USB Loader.
You'll need an SD card to launch Homebrew and such, which I'm sure you already have.
You'll need an external source like a hard drive or large USB formatted to NTFS(can play both ISO and .wbfs files) or FAT(can play ISO's under 4GB and .wbfs). I plan on getting
this, it's not too pricy and the amount of space you get for that amount is incredible.
That's pretty much all I can say so far, if I have anything to add I'll edit this post. Hope I helped ya fellow Bostonian.