There's a huge Transformers picture gallery online comprising of some 378 photos which are just about all of the on set action from the film. I just raced through them and saw some new shots of Optimus Prime, Bumblebee, and various others in transit, as well as some very cool looking stunts.

You can see the photos over at the Transformers Movie flickr pool found through Celluloid & Vinyl.

Stick with the first few pages to get to some of the more interesting action. You can even see some large blue models for Prime, obviously to help with the CGI work. This looks like to be the most comprehensive collection of photos to date, well worth keeping an eye on.