Some reporters wanted specific waivers and didn't want to rely on the blanket waivers. (BTW, Fitzgerald already knows the gov't official Miller spoke to, so the identity of the person isn't being shielded from the prosecutor and reportedly that person has already "cooperated" with the investigation.) But according to WaPo, Libby, Cheny's Chief of Staff who has also signed a blanket waiver, is the one Miller spoke to:
... two sources say Miller spoke with Vice President Cheney's chief of staff, I. Lewis "Scooter" Libby, during the key period in July 2003 that is the focus of Fitzgerald's investigation.
The two sources, one who is familiar with Libby's version of events and the other with Miller's, said the previously undisclosed conversation occurred a few days before Plame's name appeared in Robert D. Novak's syndicated column on July 14, 2003. Miller and Libby discussed former ambassador Joseph C. Wilson IV, Plame's husband, who had recently alleged that the Bush administration twisted intelligence in the run-up to the Iraq war, according to the source familiar with Libby's version.
But, according to the source, the subject of Wilson's wife did not come up.
Miller and the Times have said the reporter has chosen jail to keep promises she made to protect the identity of confidential sources. But Libby's attorney, Joseph A. Tate, has told the New York Times that he provided reporters with assurances that they could rely on the waivers releasing them to talk to Fitzgerald. Tate did not return phone calls placed for this story on Thursday and Friday.
http://www.washingtonpost.com/wp-dyn/content/article/2005/07/15/AR2005071502080.html