this is a report on the overall american mediascape in 2007 put together by the "center for excellent in journalism" which is funded by the pew charitable trust for the most part. it is an interesting and extensive mapping of the mediascape which provides some reference=points in the context of which the mapping of the funhouse might go forward.
http://www.stateofthenewsmedia.org/2008/index.php
the main page of this site features running analysis of coverage trends, on the order of this:
http://www.journalism.org/node/12653
which documents the disappearance of anything like substantive issue coverage behind the scrim of vice-presidential candidate personality stories...
-----Added 8/9/2008 at 09 : 31 : 55-----
here's another resource, geared around systemic critique of corporate media:
medialens - correcting for the distorted vision of the corporate media - corporate media issues