As widely predicted, President Bush on Wednesday officially named Fox News regular Tony Snow White House press secretary to replace the departing Scott McClellan. Putting a card-carrying member of his conservative amen corner in front of the press may signal Bush's willingness to circle the wagons at the White House or to play to his base.
As for the Dana Milbank of the Washington Post got it about right in his analysis on Countdown with Keith Olbermann last week:

"I'm not sure it would necessarily be bad for the White House, but it does raise some questions. We first have to ask if Tony's going to get back pay, and we then have to ask, is this just the beginning of a trend? Does Sean Hannity replace Rumsfeld at the Pentagon? Does Bill O'Reilly get the FBI?"

For more background on the selection of Tony Snow, ThinkProgress is probably the definitive resource for Snow's past criticism of President Bush and some of his more extreme statements on issues of the day.