You can actually try those sites that were suggested above.
Elance and Odesk are good places to hire developers and programmers as they have massive network of people from different locations around the world. Most of the time, these sites used an escrow system in hiring freelancers which makes it more conducive for clients and staff to understand their common needs.
Although you can also try other sites like Staff.com which is perfect for those who are looking to hire FULL TIME and PART TIME freelancers. Other sites don't focus in this aspect (full time hires), but this site does.
The way they hire freelancers is that they will allow you to conduct a 10-hour trial work for the staff so you can fully gauge their skills and how fast they can finish a certain project. If they perform well in the first 10 hours then you can keep going and hire them for a full time or part-time position.