Pam, I've never taught film, but I had a course in intro to film in undergrad and Kawin's How Movies Work was informative. It does not deal only with American cinema, but it situates Western film in a collective historical context. Because of its thoroughness in teaching-the-basics, it is possible to build a course around it, be it historical or political. I have a good bit of film resources in the form of articles, but I can't recommend anything until I know more about your objectives.