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