The Episode III trailer is now out and about on the internet. I can’t link you anywhere reliable, but you’ll find it if you look around. It’s also attached to the beginning The Incredibles in theaters tomorrow.
It looks fucking awesome.
Edit: I found a reliable link here.
Another Edit: Well, I guess that link wasn’t too reliable, as Fileplanet seems to have stopped offering the trailer. Perhaps try the the official Star Wars site?