Joe Conason wrote an excellent piece last week on Scott Mcclellan's revelations, retractions and obfuscations, and rightly concludes that a real Congressional investigation of this matter needs to be conducted.
Of course, if like Conason you've been paying attention since this scandal broke over four years ago, you knew already what McClellan still doesn't have the maturity to confirm - that the White House compromised national security to score political points.
Daily Kos links to Scott Horton's speculation that Bush's pardon of Libby was to cover his own ass and avoid possible perjury charges should Libby reveal that Bush lied to special prosecutor Patrick Fitzgerald during the investigation.
(Edited to correct the misidentification of Patrick Fitzgerald as "Robert". Thanks, RoJo.)