Read the following carefully documented Timeline:  

http://www.thinkprogress.org/leak-scandal
21 Administration Officials Involved In Plame Leak
The cast of administration characters with known
connections to the outing of an undercover CIA agent:

Karl Rove
I. Lewis “Scooter” Libby
Condoleezza Rice
Stephen Hadley
Andrew Card
Alberto Gonzales
Mary Matalin
Ari Fleischer
Susan Ralston
Israel Hernandez        
John Hannah
Scott McClellan
Dan Bartlett
Claire Buchan
Catherine Martin
Colin Powell
Karen Hughes
Adam Levine
Bob Joseph
Vice President Dick Cheney
President George W. Bush