Jim Henley links to the trailer that was shown at last year's San Diego Comic-con. It's isn't really a trailer. For one thing, it's a lot longer (6:23). It's also much slower, and some of the shots seem… unfinished (makes sense, it was shown quite a while ago). It's more of a showcase for fans of the books, saying: "here, this is how we took that shot, that scene, and put it in our movie."
If you're not a fan of the comicbooks, this trailer won't get you all excited about the film. If you are a fan, it won't do half as good a job as the real trailer did.
However, if you hate Josh Hartnett, you'll probably be happy to know that his scene in the trailer (a scene shown in full), should be his ONLY scene in the film.