Robert Greenwald’s documentary charges the Fox News television network with biased and politicized news coverage, and presents some strong evidence for its position. Unfortunately, it also periodically stoops to the same sort of crass insults used by Fox, and doesn’t spend as much time tweaking its competitors as it might have. Still, its methodical unpacking of routine media abuses is long overdue, and one sign of its effectivenessfollowing a couple of weeks as the best-selling DVD on Amazonwas the sudden politeness of Bill O’Reilly to guests who disagreed with him. 77 min. (JR)