This is Nottingham has a preview article today about the Harry Potter and the Order of the Phoenix DVD. It says that the DVD extras include:

“Trailing Tonks” featurette, “Harry Potter: The Magic Of Editing” featurette, “The Hidden Secrets Of Harry Potter” featurette, additional scenes, DVD-ROM content including timeline and ‘link’ to a sneak peak of Harry Potter And The Half-Blood Prince, trailers for the Hogwarts DVD, Harry Potter EA game and Lego Batman game.