You can also plug the flatmii into the dvd drive as well so you can play burnt games.
I got a flatmod first and realised it wasn't what I wanted (as my DVD drive was buggered) But instead needed the flatmii to stream iso files from the pc to the wii using a usb > miniusb cable.
It works fine. Sometimes it will lose the connection and tell you to reinsert the disk, but the interface is quite easy to use and can just click the "eject iso" button, and then mount the iso again and it works.
If you have 64bit windows though, you will need to get
[Only Registered Users Can See Links. Click Here To Register]
As the flatmod drivers won't be getting certified by microsoft, so won't install on a 64bit OS