I may have been wrong about Hulu (well, E3 is not over yet) but, Microsoft has just unveiled ESPN for 360 users.
Within "year one" XBL Gold users will have free (read - no extra charges) access to over 3,500 events. These events include MLB, NHL, NFL, Soccer, and College sports. While watching the press conference, I wonder if they will include party support so you can watch the games with friends.
The service is also Kinect compatible allowing users to play in trivia and vote for who they believe will win the match. Simple commands such as "replay" allow a user to review a play they just missed or wish to see again to rub a friend's nose in it.
Most of the events will be streamed in HD.
The impression, while watching, was that this could balloon to cover more events after "year one".
Again, it is free to all XBL Gold users.