I recommend grabbing the Transformers trailer from Yahoo (linked at Dave's Trailers Page). Something is wrong with the version from PSN...I don't know if background downloading corrupted parts of the file, or it was simply encoded with ignorance, but there are major motion artificacts. You will see objects and characters just go fuzzy.
For trailers with multichannel AVC, use Yamb to convert it. It will tell you that the conversion failed, but the surround information will remain intact. PS3 can't decode multichannel AVC, but this is useful just in case it can in the future.
For trailers in stereo, use the pass through option in Quicktime.