Well, there certainly isn't a good way to wean them off, but if you're thinking that you want to start preparing for life without a pacifier, then I'd start a little now. Like try to keep him from having it at all times, start slow, and don't start with the naps or bedtime. Start getting him used to being without it in the house while playing, or in the car or at the store. I remember one day when I looked back at myself with my son, I realized that it was more me than him with the pacifier. He certainly wouldn't refuse it, but he didn't necessarily ask for it, I'd find myself just randomly giving it to him for no reason in particular. If you find yourself doing that then don't. Also, its easier to not give it to them when they want it if you don't have it. So keep them all in his room for naps and bed only, then when you don't have one in the car to give you'll be forced to distract him otherwise. a kids song CD is great in the car, we have one and mine are now 5yrs and 3 yrs and we still listen to it. and of course I know all the words now, the best is when my husband is in the car and I catch him singing along, very cute!
My goal for both my kids was gone by 2 yrs old and my daughter was fine with that, my son was a little over about 25-26 months. But either way, I always said that I wanted it gone when they looked like they were too old to have it in their mouth. And the longer you wait the harder it is definitely! No doubt! You know your son the best, but it's not as bad as you may think it will be and its a nice relief when its over! Good luck, J.