You're a coder so you're already ahead in the outsourcing game, you can judge a people technical skills before hiring them and they won't be able to bullshit you with the typical "The RDBMS has no I/O QPS so the MVC can't connect to the furblong lasers".

In the past I've helped a couple of people like yourself and some of the tips I can think of right now are:

* Use something like oDesk to keep track of the worked hours (at least in the beginning). You'll see screencaps of what they were doing every 5-10 minutes so you know you're being billed for real work.

* Get his/her contact info. (Skype, IM, phone) and keep in touch during the beginning to make sure everything's going fine.

* Use something like Pivotal Tracker, Basecamp or any other PM tool so you know at every moment where the project stands at.

* Try to talk to the person more than once a week if possible, don't let them go rogue.

* Only hire reputable people (either through something like the oDesk reputation system or GitHub account).

* Set them up with small/test projects before giving them the full thing. A 1-2 week assignment will help you both get acquainted and you'll know if you want them to be working on your stuff. Pay them for this!

My email's on my profile, if I can be of any help just drop me a line.