The trailer is now live!
Unfortunately (for us...), there is only one brief shot of Ron, which you can find around 1:06. The trailer as a whole focuses on the young Tom Riddle and Voldemort's past.
This is what I call a good news day! ^_^
Warner Brothers has confirmed that the teaser trailer for Harry Potter and the Half-Blood Prince will debut via satellite next Tuesday evening, July 29th! If you are a very technical person, and can understand satellite feeds, more information is here!
Into the White