It was just announced (on Facebook) that a new trailer for The Hobbit will be released on iTunes Movie Trailers tomorrow morning at 7am PT and 10am ET:

To continue our celebration of Tolkien Week (Hobbit Day is only 4 days away!), we will be unveiling the new trailer for The Hobbit: An Unexpected Journey tomorrow, September 19th, at 7am PT / 10am ET on iTunes Movie Trailers.

Here’s a screenshot too (click to enlarge):

Screenshot from the 2nd Hobbit Trailer