Apple - Copy DVD to iTunes for watching on Apple TV

You can use Handbrake for this.

I highly recommend having this app in your arsenal for pesky discs that won't rip.

RipIt: http://thelittleappfactory.com/ripit/

RipIt is guaranteed to work and has a 99.9999% success rate in ripping DVDs. In fact, it has been verified to work with over 250,000 unique discs, and is continuously updated to rip the latest releases.

I would also like to mention that I own this software and I was recently unable to rip the movie "Kick-Ass". I contacted customer support with my issue, and later that day they sent me a link to download an updated beta version of the app with a fix for my disc. It doesn't get much better than that!

Handbrake was unsuccessful at ripping the first 3 DVDs I tried, but I found an older program called MacTheRipper that works great for ripping. Then I throw the ripped video files at Handbrake for encoding.