Both my boys were hugely attached to their pacifiers! I took the oldest boys paci away at about 3 1/2. We had a baby right before he turned 3, so, when he was too, I had no energy to take it away (I was pregnant and working full time), and right after he turned 3, we were adjusting to a new baby still. My youngest sons was taken away at 3 years old. With both boys, we went cold turkey. I wasn't very good about letting them only have them at night. I waited for a Friday night (so Daddy would have to endure it too :). We set them out for the fairy who came and turned them into a toy. Really, it was only the first night that was tough. It was so hard to not give in. I liked the fact that both boys were older so they could understand better. After that first night, it got a little easier every night. They'd ask for it, but didn't really cry for it (and this is from 2 highly addicted little guys). After a few days, they didn't even ask for it anymore.
Funny thing though, with my youngest, we told him that was happening that night and I caught him hiding them under his bed so he'd have his secret "stash."
I also kept their favorite ones in a special place just as a keepsake. They never knew I did that though!
*I just thought of another idea I've heard. One of my friends took their child to Build-a-Bear and had them stuffed inside an animal so they could still have them near. I thought that was a good idea, but knowing my boys, they'd have ripped that animal apart to get them out :)