I got my DVDs yesterday through amazon.com (because I had preordered them). The features on the first disc are great!
There's an extended version of the Pilot (called the "International Pilot") that has extra scenes that were cut out of the TV aired Pilot (called the "Domestic Pilot") due to time restraints.
There's also a blooper reel, James Roday's audition tape, interviews, and a commentary for the Pilot. On the other discs, there are commentaries and deleted scenes for some of the episodes. The episode commentaries are really interesting because you get to learn about stuff in the episodes that you probably wouldn't have known about if you hadn't listened to them.