I had an application on my mac to rip and convert DVDs into a divx format. The app was free and multi-platform with a cocktail glass for an icon I think.
I can't remember what it is called for the life of me.
There are dozens of threads on software recommendations such as these. If you search the forums before starting a new thread, you'll frequently find what you're looking for. Also, check the Mac Beginner's Guide. You can find lists of essential applications here and here and here.....and here.