Sorry, but encoding is a VERY CPU intensive process. Other than get a new computer with a faster CPU there isn't much you can do. Changing the output and some settings may improve it at the margins, but with your computer, you are kind of stuck.
Does anyone know how to speed up encoding in iDVD? Is there some sort of format the video should be in? .dv .mov .m4a what is the deal here... I use a g4 1ghz with a 16x lacie drive(firewire)...Thanks Much