It would appear that a brand new trailer for Batman: Arkham City will be premiered at this years Comic-Con.
Rocksteady has today been tweeting some very cryptic clues over on their twitter page, the tweets contained normal messages with some letters capitalized, if you take the capital letters and rearrange them you get;
ROCKSTEADY IS RELEASING A NEW VIDEO AT SDCC
So it would appear that we will get to see a new trailer in a couple of weeks at this years Comic-Con.