It sounds like Russert audiotaped his conversation with Libby for Fitzgerald to make the assertion which he did regarding the conversation between Libby and Russert. What are the laws in New York and Washington D.C. regarding taping conversations?
I'm not really sure, but I think it's permissible when it hurts the Republicans and a hanging offense when it harms the Demonrats.
I doubt it makes any difference in terms of admissibility into a criminal trial. Law enforcement had nothing to do with the taping. Recall it was illegal for Linda Tripp to tape Monica Lewinski but those tapes were allowed in.
One part notification in both states, so it should have been legal for Russert to record Libby without Libby's knowledge. (Link to source on post #28)
Even an illegal recording might be admissible, as with Tripp's recordings of Lewinski.