Warner Brothers has posted 3 clips of the extras included on the Season 5 Region 1 DVD. One is from a feature on Josiah Bartlet, and two are about the filming of the episode "Gaza". The third on includes this quote from Bradley Whitford: "Janel [Moloney] had a lotta dates out there" (meaing "Slab City", the barren location where exteriors were shot). You can watch them with Windows Media or Real Player.
TVShowsonDVD has a list of the extras.