You need people you can trust. Period. Go with your gut and/or get things in writing. Don't be unwilling to pay for good help. I find it better to have people I can meet in person. There are some trusted freelancers out there. Do a simple google search.

I would recommend bringing someone in. Starting up is tough and single founder companies usually take longer to take off and have a higher morality rate. The reason being starting up your own company is a very challenging process and sometimes you need someone there to keep your chin up when the chips are down.

If you are the coder for the project why not look for someone who has skills in marketing and business development? That would reduce the likely hood of them running off with the code.

peopleperhour.com - then choose the person you want by looking at the content of their bids

This is a good question, you have that killer idea and you need someone to help getting a aspect of the site going. This can mean letting them loose on your idea and development. Just one little thing that happened to me was when i joined a social site ( the biggest), i found alot of old school friends and when I got talking to a few I found alot in I.T related jobs (excellent) if you cannot trust a friend! who can you trust!