YouTube user 01MaverickTen10 posted a video explanation of the code that makes him sound like a straight-up crazy person, but the message is actually pretty intriguing. You can watch his video below, but the main gist is that there are two messages in the mission briefing. The first code uses the designate word of each mission, which is always one of the terms from the NATO alphabet (Whiskey, Tango, Foxtrot, etc.). The second half of the message comes from each mission's transmission code, which gets converted to its corresponding letter in the alphabet. So what does the message say? Skip the next sentence if you can't handle the truth!
Spoiler Alert: "Reznov is dead. Or is he dead? There was no body. Is he who he says he is?"
I haven't even played Black Ops yet, and my mind is officially blown! Check out the video below for more information on how to find the message yourself.
LINK TO VIDEO: http://www.youtube.com/watch?v=PLZlfHGo-Ro&feature=player_embedded