B.,
My daughter just weaned herself at 17 1/2 months. Here is what I did to drop feedings. When she was 13 months old, she was nursing 4 times a day -- morning, before both naps and at night. At a little over 13 months old, she went from two naps to one, which eliminated one nursing. A few weeks later, I decided to try dropping the morning feeding. I would bring her downstairs and give her a sippy cup of milk. She would be a little fussy as we were walking down the stairs, but as soon as she got her cup of milk, she was fine. The fussing only lasted a few days until she got used to our new routine. I thought I would never be able to drop the last two nursings, but suddenly last week she dropped them herself. She didn't want to nurse one day before nap, so I read her books instead. The next day, I did the same thing. She probably would have nursed that day, but I just didn't offer it. She never fussed though. A few days later, she lost interest in nursing at night and wanted to read books instead. I too was worried how I would wean her and felt like I would be nursing her forever, but my advice to you is take cues from your son. He'll tell you when he's done nursing. It may seem like he'll never stop nursing, but he will. I never believed other mothers who would tell me that, but it worked for me too. Suddenly toddlers become interested in other things (like running around and checking things out), and they lose interest in nursing.
If you decide to drop nursings yourself rather than waiting for your son, then I would try to introduce another comfort object -- a stuffed toy, small blanket or something like that. You'll need to replace the comfort of nursing with comfort of another type. Give him the comfort object while you nurse for a few days, and then just give him the comfort object and try not nursing and see if that works. If he loves to read, try snuggling and reading books before nap. My daughter loves puppies so she has a stuffed puppy she likes to have before nap and we read books about puppies.
Best of luck to you! And, remember, there is nothing wrong with nursing a toddler should you decide to nurse past age 1. People who will tell you otherwise should mind their own business.