I'd also recommend posting things on sites like Forrst. That's how I found my co-founder. I posted a rough outline of what I wanted to accomplish and asked for those interested to send me an email for more information. Ultimately, I had maybe 5-6 say they were interested with one sticking around (perfectly fine). Leverage community sites. It's definitely worth your time.

Shameless self promotion.

But http://www.weekendhacker.net is also a place for people to meet co-founders.

Currently there are approx 6000 designers and developers, 70 projects posted and all got help so far.

Looks cool, I'll add it to the list