Hey, iDVD 3 will run on a Blue and White G3 with a G4 upgrade. There was a user on here that got it to work on his. I have often wondered on how Apple's engineering does work. DVD Studio Pro 1.5 should not work at all on a Blue and White G3 but it boots just fine. I doubt that iDVD 4 would work on a G4 upgraded Blue G3 but know that iDVD 3 will work fine. Chris