The main extras are on the last disc, there are commentaries on a few of the episodes on the same disc that the episode is on. There is a fan commentary for The Two episode on the first disc, this is for the region 1 dvd box set, not sure where the features are on in region 2.
Australia (R4) didn't get the fan commentary so you may have to check locally. There was the usual Football TV Spots, Deleted Scenes, Featurettes, Gag Reel. Australia also didn't get the s4 teaser... which wasn't all that exciting anyway from what I heard.
yeah im from aus, but i got s3 from amazon, so i got the commmentary! i was wondering though, is the s4 teaser on the last disc?? i heard that it was hidden on one of the discs!
I'm sorry you guys are missing out right now. I hope the dvds come out soon for you. You will really like the deleted scenes and commentaries. The bloopers are funny also.