To find passionate developers you will need to be ridiculously utterly superbly passionate about your idea yourself. On top of that - you need to be able to pitch it to them in such a way that they subscribe to it and believe that you can execute on it. If you can't do that with developers, it might be near to impossible to do that with clients/investors/VCs.
Another thing is - if you want people to work for free/equity - what is that valuable something that you'll bring to the table? You need to highlight that very strongly and make sure that you have very good idea in regards to what weight you'll be pulling.
At any rate, if you're in NY, Boston, Seattle or Boulder areas - try to get into TechStars program. If you're around SF or have an amazing idea and fit the bill for Y! Combinator - try to get in their program. They could actually help you to find technical cofounders, but you gotta be really passionate and clear about your idea...
Another thing you can try is going to tech meetups. There are tons of them in major tech hubs(SF, NY, Boston, etc.)
And finally here are few useful links:
How do I find a technical co-founder?
Non-hackers: how to find a co-founder