I'm still nursing my 17 month old 2-3x/day, but my supply is really dropping, which has taken the decision of whether or not to wean mostly out of my hands.
I find myself rather sad about it, and even though I was slowly weaning her before getting pregnant, I'm actually allowing her to linger a bit longer on each side and not trying to avoid it at nap (something I was doing). Let her get all the mama milk she can while it's still there.
ATP: my daughter also always nursed to sleep, but I changed up our bedtime routine a few months ago so that there was something really cool *after* nursing (this really cool thing is a "Twilight Ladybug" that shines stars and a moon around her room - it's incredibly relaxing for me, too, and my DD absolutely LOVES the moon, so it was a good choice for her). I nurse her for about 5 minutes a side so she is still awake, then lay her down in her crib, then "turn on the moon". I lay down beside her crib and offer her my hand, or let her touch my face or hair. She did not like this being put down awake thing at all initially, but the novelty of the ladybug glowing and the lights around her room was a great distractor. Sometimes she stands up and walks around her crib, or plays with her feet in the crib rails for a while. If at any point she becomes upset, I talk quietly about our day, what we did, who we saw, how funny our cat is, that we did or didn't see the moon that evening - anything I can think of that might catch her attention, and/or offer to rub her back or head. Eventually, she actually settles and falls asleep. It has totally changed bedtime and she's sleeping so much better at night now.