We went through the same thing with my son. I believe the ONLY way to successfully get them to kick the pacifier habit is to go cold turkey and take it away from them. At his age, it will be a bit more of a challenge than if you had done it when he was younger (we got rid of it when our son was one year.) But even so, it can be done if you persist. Set a date about a week away where he will no longer get the pacifier. Talk to your son all week about how in 6 days (5 days, 4 days..etc) the pacifier will be going bye-bye for good. Mark the date on the calendar and show him everyday how the date is getting closer and closer. Then, before he gets up on the big day, take all the pacifiers in the house and throw them out! He will probably be quite upset about not having his pacifier for a few days. Expect tantrums and a rough couple days. But if you give in at any time and give him a pacifier, you will be starting back at square 1 and he will have learned that if gives you a hard enough time that you'll just give in. You do not want that to happen. The key is to persist and not give in. To try to make the transition easier, try to have lots of activities planned for those first few days to keep him busy (i.e. distracted!) as much as possible. If he's used to having the pacifier for nap times or going to bed, expect those times to be especially difficult. Again, you're just going to have to grin and bear it and you might have a couple sleepless nights. Stick with it though and it WILL work. I promise!!!! Of course, if you let him continue having the pacifier, he will eventually outgrow it. I don't see too many highschoolers with pacifiers. :) So you could always just let him keep it, but know that he may not want to get rid of it on his own for quite some time. I think it's a good idea though to kick the habit now because at his age, it can cause problems for his teeth and palette formation in his mouth. This can lead to both dental and speech problems. Also, if he's used to having it in his mouth a lot, it could stunt his language development because he probably isn't talking as much (or as properly) as he would be without it in his mouth. You can talk to your pediatrician about all this to see what his/her opinion is, but that's what I've heard.
Good luck to you and let me know how it all turns out!!
~L.