Twitter. No joke, we were both looking for partners to enter an app challenge, found eachother on Twitter, won, and now have a company (we're going full time very soon).
The first guy I met through a friend. I met the second guy while I was a project manager on some application at work. He was a contractor on the project and we had great chemistry. If you have an idea and you find someone that is as passionate as you are about it, I'd say that's a pretty good start.
I know this might be a little unorthodox, but I met mine on a strange chat that was hip on the 90ies. Granted, never met anyone like that again, ever.<p>Also, she is my girlfriend, too (if that counts for anything).