I've only been looking at online freelance sites and have had the most success at oDesk. In the past I've picked up a gig or two on Craigslist, but there was more legwork required to get gigs and I stopped.

The amount time spent reviewing and applying to jobs is such that I don't intend to keep at it for a long time - but it is definitely a means to keep an eye on what (mostly) small businesses and hackerless startups out there want enough to pay someone for.