Go over to VideoHelp.com's guides and filter on "XviD to DVD" and "DivX to DVD" and also "AVI to DVD".

I've had decent luck with a tool called "DIKO". (You'll have to search for it.) It's slower than some processes that take three different tools, but it's all in one, so you can pretty much set it to go and come back later with a DVD image ready to go.