I almost missed this one.  Picked up on it while perusing the Huffington Post:

Scott McClellan, President Bush’s former press secretary, says he is backing Barack Obama for president.

McClellan made the endorsement during a taping of Comedian D.L. Hughley’s new show that is premiering on CNN this weekend. The former Bush administration official said he wanted to support the candidate that has the best chance for changing the way Washington works and getting things done.

McClellan follows Gen. Colin Powell as the second former member of the Bush Administration to endorse the Senator from Illinois.

Maybe I’ll buy his book now.