I am trying to wean my 18 mth old daughter from nursing at night.?

I already have been able to wean her from the day-feeding but at night is the really hard thing! She does NOT go to sleep. She sleeps on a bed already so if I let her "cry it out" she gets up to come get me. Please anyone who has gone through this, how did you finally overcome this?? oh and another question, my little girl is 18 mths, 35 inches tall and weighing 35 pounds. Im also worried sick that she might be too heavy, but she really doesnt eat that much and she eats healthy!! Thank you all for you answers..........