I just watched a program on the History Channel about the political implications of comic books. I bought the DVD and showed it to my students and they loved it!
I'm thinking this is the one. It really is a good program. It not only discusses the political world but also the social world and how revolutionary (and risque) some comics were, especially the horror comics. Highlights include overview of Batman and Robin and Frank Miller's run on Batman. I was disappointed in how little X-Men were discussed because they are endless in their social, political, and literary parallels. But I didn't make it, so I can't complain. It's well worth watching for your classes.