Seth over at Stephenie Meyer's website confirms that the Twilight DVD will be released on Saturday, March 21st. He also reveals these details:
SPECIAL FEATURES — DISC ONE
* Five extended scenes with director introductions
* Audio commentary (Catherine Hardwicke, Robert Pattinson & Kristen Stewart)
* Three music videos (Muse, Paramore, Linkin Park)
SPECIAL FEATURES — DISC TWO
* Five deleted scenes with director introductions
* Seven-part documentary: "The Adventure Begins: The Journey from Page to Screen"
* Comic-Con Phenomenon featurette
* And more!