If you want to see a smackdown of a bloviator, have a look at this post by the estimable Juan Cole of National Review figure Jonah Goldberg. Cole is a prof at UM who maintains probably the best English language source on Iraq in existence in his blog Informed Comment.

Students in CM 530 have been asking--well, one of them, at least--how it is that one can judge reliability of a news source. I think that consistency over time and expertise are pretty good starting points.