How can I watch my home movies on the wii. I have installed the app for dvds, this works fine for for normal dvds. However when I try to convert my mini disc to a larger one the wii wont read it. Will I have to use a sd card.

you could just take the AVI or Mpg2 file from the mini dvds and play them from the SD card.
But it should not differentiate between a home made DVD and a Commercial one, so you might be burning it wrong.