All the popular blogs are trying to leverage job boards to make some extra income. Guy Kawasaki, ReadWriteWeb, Problogger… you name it.
Needless to say that in order to create an active and profitable job board you need first to have a blog focused on a specific niche, and a decent amount traffic.
The advantage of this method is that it is passive. Once you have the structure in place, the job listings will come naturally, and you can charge anywhere from $10 up to $100 for each.
List of popular job board software: