The Winter 2005 issue of the Nieman Reports has many articles about the news coverage of Evolution and Global Warming. Both topics, of course, are ill served by the tradition of "he said, she said" which gives undue prominence to advocates from the Discovery and Competitive Enterprise Institutes. You can read the entire issue (5.8 MB PDF) or just the Intelligent Design section, the Global Warming section or the Global Warming section with multimedia (2.3MB PDF+QuickTime).
As the somewhat tongue in cheek Colbert Report on Comedy Central in the US asks;
"How does one report the facts in an unbiased way when the facts themselves are biased?
... its become all too clear that facts ... have an anti-Bush agenda."