So? Cheney has security clearance to possess that info, and so does Libby. Conversation between the two of them does not constitute any prohibited disclosure, unless others without clearance were present or were shown the Libby's notes later.
it has no merit factually, unless Cheney testified under oath to the contrary. on the spin side, the media will spin any indictment of Libby into a "he lied to cover for Cheney".