GameSpot has a new trailer and interview with RockSteady confirming that Catwoman will be a playable character during parts of Arkham City.
She has her own style of movement and combat as well.
Ginn wound down the Batman portion of the demo by heading over to a roof which had a conspicuous group of cats hanging out. Once Batman was near the cats a new context sensitive option, titled "take a break," appeared. When the option was selected a cutscene was triggered and Catwoman popped out from the shadows, as she does, and gameplay shifted to her.
Not sure how I feel about this. Hopefully it wont disappoint but i never liked catwoman.