A live report (RealPlayer) from Julian Borger of the Guardian reveals that, yes, Bush press secretary Karl Rove was the one who broke the law by revealing the identity of a CIA operative, but that the reporters in question aren't admitting it publicly yet, as to do so would reveal their source and undermine their credibility.
Two of these reporters identities are known -- one was Andrea Mitchell, and, of course, one was Robert Novak. I have to wonder whether these journalists have considered the fact that they weren't just talking to a source, but were, in fact, material witnesses to a crime, just as surely as if during the course of their conversation with him, Karl Rove had shot someone.
One has to wonder whether they could be charged for aiding and abetting a criminal act...