Xbox Live Gold members will get access to the Madden 10 demo this week. A freshly posted press release promised to give us the download on Thursday, a full week before PS3 and Xbox Live Silver members.
This is separate from the Super Bowl demo you get from pre-ordering the game from Gamestop. This one here is the public demo that will feature a night game between the Dallas Cowboys and the New York Giants. The game itself is due on on August 14.