Personally, I'm creeped out by craigslist but if you find something good, then go right ahead. lol

Temp agencies, if you can't find some by doing a Google search, look in your local newspaper or their online version and you'll see that they have ads posted with something like "looking for professionals" and it lists more than one position. Those are usually temp agencies. If you do a monster search or any of those search engines that have company profiles, you'll see on those pages they are temp agencies.

I'll give you an example of a local one that I know of so you can see kinda how they are: Sparks