“I’m working with iPhoto and iMovie on a G3 Mac. I want to make some short DVD‘s of my stuff. If I find someone with a G4 and iDVD can they convert my movies into a DVD? Also, can I use CDR to make short DVD discs?”

There are several questions hidden in here. First, iDVD can certainly make DVD material from your iMovie output. There is a special export function in iDVD for this. Take that exported file to the G4 with iDVD and you can do the rest from there.

You can use CDR to burn DVD’s, but not from iDVD. This will require a more generic burning program such as Toast. Your best bet is to get DVD Studio Pro and author your own DVD content, and then use Toast to burn it on to discs. You should use CD-RW though, because the wavelength of lasers used on them is much closer to DVD than CDR is. This will allow them to work in most modern DVD players.