I have a friend who does medical coding or billing from her home. She works on a contractual basis for a couple of local doctors; however, she has years of experience and worked in medical offices first, which is how she made her contacts. I don't know much else about that particular field though. What are your skills? Employment background?
Personally, I would stay away from those internet ads, too. If they were as wonderful as they claim to be, everyone would be doing it.