MacTheRipper is a free DVD ripper (extractor) for Mac OS X.
It can extract commercial DVD movies to your hard drive, minus all the copy protections and region controls put in place by DVD publishers. You can then use various tools to burn the movie back to DVD-R for use in DVD players, or convert the movie to different formats for playback with a variety of devices.
MacTheRipper is intended to backup DVDs you have legally purchased for personal use. Any copyright-infringing activity you choose to perpetrate using this application is illegal, immoral, and beyond our control.

You can get mac the ripper right here.