To my knowledge, neither the Cockpit Voice Recorder (CVR) nor the Flight Data Recorder (FDR) for either flight were recoverable. The recordings in the previous post were obtained from the various Air Traffic Control (ATC) facilities involved...
Clanad is correct, those links are transcripts of conversations with ATC. The CVR for Flight 93 (the one that crashed in Pennsylvania) was recovered, but I don't believe the contents have yet been made public.