Here is just some rumors and other stuff from wikipedia:
* A beat-up Chevrolet Camaro as Bumblebee (the sighting of both an older-model Camaro and a Saleen-modified concept Camaro suggests that Bumblebee will get an upgrade at some point during the movie).
* A military mine-clearing vehicle named Bonecrusher (the sighting of a large military vehicle marked “Bonecrusher” seems to confirm that this will be the final name for this Transformer).
* A Decepticon police car named Brawl (the sighting of a Saleen-modified Ford Mustang police car on the set confirms this). Current name is unknown but it is unlikely to be Brawl.
* A large tank named Devastator (an on-set sighting of a modified tank with two different turrets seems to confirm this, though Bay specifically used this one as an example for a script-name that isn't the real one). In fact, this character may actually be named Brawl, just like his G1 namesake.
* A mechanical scorpion appropriately named Scorponok (mentioned in an interview with director Michael Bay on Ain’t It Cool News; a newspaper article in the Northwest Florida Daily News confirms a scene between the military and a large mechanical scorpion).
* A Special Ops helicopter that can deploy “minions”. Originally slated to be Soundwave after early CG cinematics were shown at San Diego Comic Con in 2005, but this may have changed after Hasbro made it known they wanted Soundwave to have a musical device mode in the movie. In early drafts of the script this character was named Grimlock, then according to Murphy was named Vortex. Current name is unknown, but is rumored to have been changed for a fourth time.
* A boom-box Decepticon, whose transformation is rumored to involve "stretching", leaving him with a four foot tall robot mode and who appeared in a Februray 2006 version of the script as Soundwave. Extreme fan backlash over the character has led to the character being renamed and Soundwave being held over until a sequel, where Murphy said at a recent fan con "...we can get him right." The character was rumored to be renamed Soundbyte, but this has recently been dismissed by official sources. The character now seems most likely to have been renamed as Frenzy, after the G1 character who was a minion of Soundwave.
* An ambulance (previously a fire rescue vehicle) named Ratchet (was mentioned during pre-production by Murphy several times).
* Fan-favorite Jazz, originally a slant-nosed Porsche 911 but described in early drafts of the script as being a "cool sports car".
* Autobot Ironhide has apparently replaced the controversial choice of Arcee in the February 2006 draft of the script. His alternative form is rumored to be a pickup truck, but this has yet to be confirmed.
* A long-nosed cab fashioned with red/black-flames artwork has been seen on set; discussion with Bay representatives seems to affirm this is indeed Optimus Prime's alternate form.
* Cybertronian forms and alt modes as well as Cybertron itself are hinted at making an appearance in the movie.
EDIT: Found this E! thing abute transformers: Enjoy!
http://www.bayfans.com/news/2006/july/index.php?page=0711b
