Well, I have weaned a dummy from both of mine. Nathan was 2 and a half and Alex was 9 months.
The way I dealt with it for Nathan is to work on the 'Big Boy' tactic. He was due to start at playschool and I said that he was big now and shouldn't need a dummy. (Shame that, on his first day there was kid, bigger than him, with a big dummy sticking out of his mouth!)
Anyway, we also worked on Father Christmas. I said that he was watching and if he saw Nathan with a dummy he might think that he was a baby and bring him babies toys. That sort of did the trick!
Perhaps you could try to do it for naps first, let her have the dummy to get to sleep and then take it away and not reintroduce it during the nap. Eventually encourage her to fall asleep for naps without it. If you are successful for naps, then bedtime should be easier. What do you think? That's how I did it with Alex (9months)
I hope that helps.
mari