They're hinting it, since they're always seen together, Jackson says that he's got a crush on her, and they even kiss in an interview. Oh yeah, and he gave her a teddy برداشت, ریچھ in Vancouver... So I'd say that yes they're dating :]
*UPDATE* They aren't dating, but that's only because they don't have enough time to actually DATE. But they both really love each other :]
Well, I myself want them to be together - they looks so cute! I don't know how to interprate Jackson's words, but I think that he says that SOMETHING is between him and Ash. I: What can آپ tell me about New Moon? J: (Cut)… I think we have a lot مزید action, and a lot مزید steamy love affairs. I: Ooh, tell me about the steamy love affairs. J: (Cut)…The chemistry is amazing. Myself, I love working with Ashley Greene. Easiest thing in the world, having chemistry with that girl. I: *serious face breaks into a wide grin* Not hard, was it? J: No, no, hardest part was saying goodbye at the end of the day.
i think they are i know for sure he has a crush on her. but if u google" ashley greene and jackson rathbone dating, and u click the 1 tab and look at the pictures they look like they are. im pretty sure they are