Via CBS's Mark Knoller:
UPDATE: More from the pool reporter:
Under gray skies and intermittent drizzle, President Obama boarded Marine One at 9:30 a.m. EDT in an open press event.
A few White House regulars were atwitter (and on Twitter) when the President walked directly up the steps of Marine One without saluting the Marine on duty. He soon came out of the helicopter, walked down the steps, shook hands with the Marine and engaged in a brief conversation.