Hi, Brandy ~
This is a toughie - at least it was for me - with a boy. I've gone through two boys and neither one of them was cooperative in the process. Both of them are of above average intelligence. Our older boy is probably gifted. Has nothing to do with it.
We tried EVERYTHING the first time around: plenty of encouragement, parties (complete with confetti), stickers, coins, special treats, even Dr. Phil's "fool-proof" method. And we didn't rush him into it at all. Eventually I gave up and decided he'd do it when he was ready. Well, my mom came over one day when he was 3 1/2 and he asked her to change his diaper. She said if he could do that, he didn't belong in diapers, so she stood in the bathroom with him until he went. A little forceful, in my opinion, but she did in 20 minutes what I couldn't accomplish in a year. And I had no complaints when he never again used a diaper.
My younger son was interested way before his brother, probably because of his brother. He wanted to be a big boy like Michael. But we still struggle with occasional accidents (#2 accidents, anyway) and he just turned four.
We bought my daughter, who is 21 months, a potty a couple months back, but she's shown no interest in it whatsoever, so we're still waiting on it.
Each child is different, Brandy. I've found sometimes it's best to push the issue and sometimes you shouldn't. Not sure how helpful this was, but hang in there! You know, since you have older ones, that this phase doesn't last forever. :)
~ R.