So many have written so much that I'll just refer you to them for any part of this story you are not familiar with:
AMERICAblog was all-Gannon-all-the-time for a few days last week; scroll down for the juicy stuff. John also gave Aaron Brown an earful on CNN Newsnight. Atrios this morning rips Howard Kurtz (WaPo media bloviator) for his most recent hypocrisy. But the best comes from a snark-only thread at Daily Kos, whose diarists essentially broke this story (appearing as a correction):
For the Record: The journalistic alma mater of 'Jeff Gannon', where Mr. Gannon studied journalism in an intensive two-day, all-meals-included course costing a full fifty dollars, is in fact known as the Leadership Institute Broadcast Journalism School and not, as I had previously referred to it, the Morton C. Blackwell Institute of Media Whorticulture.
Which brings to mind the immortal words of Dorothy Parker:
"You can lead a horticulture, but you can't make her (let's make that 'him' as well) think."
Update: I should have mentioned that Salon's Eric Boehlert -- who was also on Newsnight with AMERICAblog's John A. -- has a great synopsis, and that Crooks and Liars has a video of the CNN interview, the transcript of which I linked above.