The USG's position is that Kiriakou left the CIA and, in an effort to drum up consulting business and sell a book, told journalists on several separate occasions about (a) the identity of a covert operative who was still undercover, and (b) the affiliation of another USG employee to a program to a classified program capture Abu Zubaydah. Kiriakou was questioned by the FBI and, the USG claims, lied about his disclosures. Kiriakou himself had, according to the USG, repeatedly claimed he hadn't intended to compromise either operative, the subtext apparently being that he assumed the title of "whistleblower" when it became convenient to his defense.

FAS does a great job tracking all these leak investigations:

http://www.fas.org/sgp/jud/kiriakou/

I don't know what to think about this case. It's not the most sympathetic case, but certainly not the least. But I'm also biased, because I think both Guantanamo Bay and the rendition programs were abhorrent.