Oh yeah, there's this poly crowd for cool people, you know, only some people qualify.... Haha just kidding!!
There are many poly "signs" (wikipedia has a list of them I'm sure there is a list of them on the forum also). There are also conferences & workshops.
I think that trying to "convert" people would not accomplish what you desire. You can certainly introduce them to the idea. People have to evolve on their own you cant make them. If they are open minded, that is a great start.
Honestly I think the easiest way to start a relationship is with someone who is at or close to the same stage (emotionally, physically, spiritually, mentally) as you. Naturally polyamory creates an environment where people are constantly challenged/nurtured, so there is constant self growth. So I can see how poly people that have already experienced the lovestyle would want to join with others that have some experience, or are at least already open to the mindset.