I wish someone told me this a while ago, because it's one of those things that makes you go "doh" once you figure it out. I found our early adopter at the most obvious place of all, and truely had no clue until I sat down with him for a drink - he liked talking about technology & so did I.

 My company sells technology to a typically technology resistant market, go figure.  I went to an industry conference and, since I was exploring porting our product onto the Blackberry, strolled over to a talk about about Blackberry solutions in my space.  The talk was rated as being very technical, but the person who was leading it had the following characteristics:

1. Beta tester of products
2. On the edge of implementation (ex: has rolled out Instant Messaging software for communication w/ clients, has a 2 panel display for all employees!)
3. Most certainly could kick my ass when discussing any sort of technology (which does not mean much, to be frank)
4. A former consultant & entrepreneur
   
5. Male (not sure if that  makes a difference)

So now that I've said it, you probably are thinking "that's obvious." It sure sounds like it but finding those people is hard so my advice to you is go to educational conference where people (hopefully the buyer) is presenting to other buyers in his/her industry, industry conferences attended by the buyer, etc.