Leaders at the Crossroads

We have several student's right now who are natural leaders. The other student's look up to them and try to imitate their every move. Unfortunately, these leaders are usually our worst discipline problems. Here's an example of what I'm talking about.
Brad is a 7th grader who is very outgoing. He hugs teachers, is very friendly, and he has chosen to display very gay mannerisms. While this bothers some of his male peers, the girls love him. The teacher's would love him to, if we could get him to not be so "outgoing" in the middle of class. If he has a thought, he says it, at his loudest voice. His little followers often follow suit in an attempt to gain his approval.
Now, if we could just harness Brad's abilities, he could be a wonderful influence on the other students. But how do we do it? How do we convince this 7th grader, who thinks adult's don't know Jack, to make good choices?
That's what I have to figure out.