Karl Rove has been identified by AP's sources as "Official A" who is a prominent player in the Libby indictment:
Friday's indictment says "Official A" is a "senior official in the White House who advised Libby on July 10 or 11 of 2003" about a chat with Novak about his upcoming column in which Plame would be identified as a CIA employee.
Late Friday, three people close to the investigation, each asking to remain unidentified because of grand jury secrecy, identified Rove as Official A.