from danger room: The Web site Government Attic says NORAD and U.S. Northern Command "have released a copy of their audio files, telephone conversations and situation room discussions, from the terrorist attacks on September 11, 2001." And governmentattic.org has posted them all to its site, in .zip files linked within a .pdf document .
it was a little labor intensive getting to the files & i think they're mislabeled. so i've sorted them out & saved you some headaches. here are the direct download links: