How do unlock call of duty world at war nazi zombies?

In the menu you look down at your feet using the anolog stick and repeatedly press Rt and Lt until you stand up walk around until you find the computer, when you find the computer you hit X(xbox-360) or square(ps3) then type in 3arc unlock then press enter it should say cheat enabled on the screen, then hit x or square to exit the computer and then hit a(xbox-360) or x(ps3) to sit back down, go to Zombies hit psn or xbox live, solo, or system link and BAM you have all 3 maps unlocked for Call of Duty Black Ops :) sign: Matt