Your best bet is probably oDesk. Unfortunately, they do not accept bitcoin that i am aware of.
If you are insistent on keeping the money in this community, it would be wise to have 3rd party code review commissioned, and have the transaction escrowed.
Theoretically, the way you can accomplish this to protect both parties:
Client places money in escrow
Developer provides online accessible demo for testing
Client notifies escrower to request code
Developer provides code
Escrower releases funds to Developer
Everyone is happy.
It might also be beneficial if you could throw out more specific details, and an estimated budget.
I am definitely planning to use escrow. The third party code review is an excellent idea.
I will post a more complete description of what I am looking for at some point today.