The news that Andrew Card is resigning as Chief of Staff is not entirely unexpected, but it hardly represents a sea change in the way the White House will operate. His replacement is budget director and former deputy chief of staff Josh Bolton. It does not, as The New York Times notes, "represent an infusion of new blood."
This is part of a broader move by the White House to push up the sinking poll numbers. Another tactic is to have private informal meetings with members of the press.
I think all these moves are wasteful. The White House problems don’t stem from bad PR, but bad policies. If they want to turn things around, they simply have to change their policies, not their public face.