You have not referenced location but I am thinking a similar question on startups exchange that I answered is likely to help you.

http://startups.stackexchange.com/questions/8576/how-to-build-a-startup-freelance-software-qa-in-the-us/8585#8585

Note that rates are higher when you travel and work on a clients site, as opposed to working from home. I've been a freelancer as you call it since 1994 - Working from home brings problems of miscommunication with the customer and can lead to headaches. See another question I answered http://freelancing.stackexchange.com/questions/4266/client-threatening-legal-action-constantly/4286#4286

I'm not suggesting you do or do not work from home, but I'm just pointing out that the work can be rich but money is not free.

In Europe, most of my contracts have come from jobserve.com

Best of luck!