For my "Media in Society" course, one of the texts I use is the classic _Media Monopoly_, by Ben Bagdikian. Although its overall focus is on newspapers, much of the book touches on television, and the arguments about media ownership and advertising are very generalizable. Its also a very well written book, and most of my students seem to like it. A new edition has just been published by Beacon Press. Hope this helps! Matt McAllister, Virginia Tech