Fearless White House correspondent Helen Thomas has covered nine presidents, and says Bush is undoubtedly the worst. It was the talk of the blogosphere: As part of Stephen Colbert's eviscerating roast of President Bush at the annual White House Correspondents' Association Dinner in April -- wonkish Washington's equivalent of the Oscars -- he showed a hilarious video that was supposedly an "audition" for the job of White House press secretary. His costar in the satiric short: none other than the octogenarian doyenne of White House correspondents, Helen Thomas. Using actual TV footage of the White House press corps, Colbert (of...