Nice equipment you have there BAtoload, and Morgwen sure went to a lot of work to help you.

For installing the stuff, just follow the directions that come with the installers (I'm assuming you are using Panther). If you are on OS 9, the Indeo codecs are just dropped on the system folder, but if no dialogue pops up, drag them to the extensions folder and QT will find them.

For help with your other questions, try the Apple G5, Panther or QT forums at http://discussions.info.apple.com. The iMovie forum gets quite detailed about hardware connections.