The Reel Directory is basically a Yellow Pages for the film making community. They have listings for location scouts, stunt drivers, post-production services and any other resource that a producer needs to make a film. Including listings for agents, casting directors, headshot photographers, and even actors themselves. A terrific resource for mailings.
You can get the book, sets of mailing labels, or just keep track of what's most current on their website. Also on their website is a page called 'production hub' which has listings for projects that are looking for crew and/or actors.