I know it has a USB port in the back, so I'm wondering if it reads them.
I don't think it does. I once put a flash drive in there but nothing happened.
I am 99.99% sure it doesn't.
but I hope Nintendo makes a external hard drive soon, with all the the VC games and WiiWare games that are out, the Wii doesn't have a lot of Memory to store all those games...
I doubt it. It charges devices via USB though.