Available over at StarWars.com is a new promotional music video for Revenge of the Sith, entitled "A Hero Falls." Essentially an extended trailer, it does feature some new musical cues (remeniscent of "The Ten Commandments"), and many unseen clips from the film. Story wise, it's a little spoilerish, but nothing is revealed that wasn't already fairly common knowledge.
Here are the other Ep. III videos.