Since this games was bought by a lot of people, and when i say a lot i really mean A LOT..
Thought some1 could be interested in trying this codes..

The Call of Duty: Black Ops load screen features protagonist Alex Mason strapped to a chair. By using a little ingenuity and elbow grease, along with the “Aim” and “Fire” buttons (LT/RT on 360, L2/R2 on PS3), you can wriggle free and explore the room. Once you stand up, turn around and head to the back of the room, where a computer awaits. Enter the codes below to unlock various bonus game modes and hidden content.

DOA – Activates Dead Ops Arcade, a top-down, two-joystick zombie shooter.

HELP – Displays a list of system commands in the terminal, gives Pentagon User E-mail access.

DIR – Displays a list of audio files and pictures that you can open using the CAT comman.

CAT – Lists all the unlocked audio files and pictures, opens specific files.

WHO – Displays a list of login names you can use with the RLOGIN function, though some of them are password protected.

3ARC INTEL – Unlocks all the Intel available in the game.

3ARC UNLOCK – Unlocks, Dead Ops Arcade and Presidential Zombie Mode.

ZORK – Unlocks Zork I: The Great Underground Adventure, a text-based adventure game from 1980, which you can play from within Black Ops. Go figure.

This “Top Secret” Codes were found on Agent 002 Codenamed FileFront