I'm amazed more people aren't paying attention to this. First the people who did this are almost certainly going to deny and lie their way out of it, they probably already have statments like that on record.
The justice department will probably have no choice but to investigate it. Anyone who did this is facing years in jail, at the least a criminal record. Anyone who covers it up, and there must be many lower aides would be facing conspiracy charges and jail time. A lot will depend on whether the judges have discretion to not award jail time for this, I don't think they can avoid it.
The worst part is it's common knowledge who really did this as several journalists were approached. Someone is going to leak exactly who it was and it was according to Wilson Rove and some associates which means the Cheney, Bush and others knew either before or after the fact and failed to come forward and report a crime. In total most of the top people will be guilty of a jailable crime and the only thing stopping this is either more lying or a pardon.
If they manage to squash the investigation this will be such a corrupt act that the press will be enormously detrimental. My guess is whoever did this might resign very soon.
Rove and Cheney may be gone within months.