This reminds me of Drew Wilsons project http://builditwith.me/
We are fully aware of Drew's project and think it's awesome. We are a different service in that we match based on skills, have a invite-based system, provide built-in chat, and help promote the project on our website once you're finished.
We're also solely meant for side-projects that may or may not go on to become fully-functional startups.
Because he's busy working on other projects, the site's content has grown a bit stale: There are many ideas coming in, but not many people are working to execute them.
There's also no way to remove your account or update it to reflect you're no longer available or interested in collaborating. I've emailed Drew numerous times asking to de-activate or de-register my profile but I've yet to receive a response.