Vice President Dick Cheney was the one who leaked Plame's identity. His Chief of Staff, Scooter Libby, likely attempted to obstruct justice by informing the special prosecutor that it was Journalists, including NBC's Tim Russert.
It is starting to get very interested. Reports have already come out showing that Bush himself knew about the cover-up, or at the very least that Karl Rove and Scooter Libby revealed the identity months if not years ago. Yet, he went to claim that D.C. was a city full of leakers and that the identity of the leaker in this case may never be revealed. Well, despite all of Bush's efforts, that identity was revealed. It was revealed to be #2, Dick Cheney.
This leaves a lot of questions to be answered. Who will be indicted? It seems that at the very least Scooter Libby will be among them. Between trying to throw off the Special Prosecutor and sending a letter to Judy Miller in prison that can almost assuredly be deemed as an obstruction of justice, it would be hard to imagine that he won't be indicted. The question is, does Special Prosecutor Fitzgerald have enough to implicate Dick Cheney? It would probably be very difficult to go after the Vice President with the same charges of corruption - perjury, obstruction of justice and the like, that could be used to go after Libby and Rove. For Cheney to be charged, Fitzgerald would probably need some key piece of information that shows he used Plame's identity purposefully, knowing it was a secret identity, to hurt political opponents.