Doing some researching and writing earlier this month, I was trying to decide on an appropriate occupation for a character I was creating. One of the most helpful online resources I found was the Occupational Outlook Handbook published by the U.S. Bureau of Labor Statistics. If you visit the site, go to the search box in the upper right hand corner and type an occupation. If your search terms are too specific, just make it more general (e.g., try "dental" instead of "dental technician", which will give you lots of results). Eventually you should be led to an overview of the profession you're seeking, including the types of wages that might be expected, the type of education required, and so on. Useful stuff for writers, particularly the stuff about the downsides to each job. Can you say "conflict"?
Of course, besides its usefulness to writers, people that are actually, you know, looking for jobs might appreciate the link, too. Being the lucrative, high-demand profession that independent filmmaking is, though, I doubt many readers of this blog would ever need to use the site in this way.