They have it up on the official page. I don't mind telling you to go watch it, because there are no commercials in it. It is itself a commercial and it is awesome.
Lost - Season 4 Trailer
In other news, it looks like some shows are coming back on the air. Leno and Conan, Kimmel, as well as The Colbert Report and The Daily Show. After reading statements from both Leno and Conan, I have to say that I don't envy their position. That is a tough call to make. While it will weaken the WGA's position, I can't fault any of them for seeking a way to help people keep their jobs. So, kudos to you guys for being ballsy, and I hope that it is because you are being ballsy (and not because you fell to pressure from the studios).
To end it all off: an interview with actor John Hurt (who is rumored to be playing Abner Ravenwood in Indiana Jones IV). I'm very excited for this movie, and had completely forgotten that Sir Shia was in it. There is a slightly strange picture of Shia looking like a greaser in it. I guess that would make sense given the time frame of the other movies.