The teaser trailer is coming in the next 2 months.
In May, attached to the new Star Trek, an extended, long trailer will be shown.
Sideswipe (silver Corvette)
Skids (green Chevy eco-friendly van of some sort)
Jetfire (rumored to be SR-71, might begin as a Decepticon and switch sides - combines with Optimus!)
Arcee (3 motorcycles combine to form her)
Megatron (might be now called Galvatron) - Cybertronian tank - same colors, not purple!)
7 construction vehicles, multiple colors, forming Devastator
Soundwave - a satelite, then a pickup truck, though that's denied
Ravage - somehow works with Soundwave
The Fallen - unkown (comic book guys - chime in here, please)
Barricade? (nothing is known here, but it's possible)
Scorponok? (we don't know)
Jazz is not coming back. His voice actor might be playing another character.
There are no triple-changers. They want to save that for TF3. Get it? "Triple?" That's so creative.
There is some kind of transforming ice cream truck. There's no word on whether it is an Autobot or Decepticon, but it may be a combiner formed by Ben & Jerry.
Agent Simmons (Sector-7 was disbanded though)
Leo (who was this?)
President Keller (rumored)
Fig lived through his wounds fighting Scorponok, but the Prison Break actor was not able to film for TF2, but wants to do TF3.