Season One DVD will be released on September 5, 2006.
According to TVShowsOnDVD, season one DVD will be released on Sep. 5th.
Extars will include unaired scenes, gag reel, cast and crew commentaries, Supernatural: Tales From the Edge of Darkness, a day in the life of Jared and Jensen and a sneak-pick of season 2.
For more details check TVShowsOnDVD.
Thanks to Immortal Goddess and EllaBella for the information.