Code                Effect        
!cut to the chase   Mission skip   
!rate me            Debug mode   
!the meek           Mission failed  
!oh behave          Disable tan AI   
!mojo               Enable tan AI   
!heavenly glory     Unit receives three bombing airstrikes   
!this one goes to eleven Unit receives three napalm airstrikes  
!peep show          Unit receives three recons   
!johnny ricco       Unit receives three paratroopers   
!i woke up this morning Unit receives nine blue disguises   
!incognito          Unit receives nine gray disguises   
!no sunblock        Unit receives nine tan disguises   
!whistle and flute  Unit receives flak jacket   
!yippee!!!          Unit receives unlimited ammo sniper rifle  
!roody-pooh         Unit receives unlimited air attack   
!florence           Unit receives unlimited plastic mending kit   
!i like to keep this handy Unlimited bazooka   
!patty melt         Unlimited flamethrower   
!you want some      Unlimited grenades   
!hello neo          Vulcan machine gun   
!i got two words for ya... Minesweeper   
!sprinkles          30 mines   
!disco inferno      Unit on fire   
!disco is dead      Extinguishes fire   
!italian job        Large explosion   
!door               Teleport unit to pointer location   
!pump me up         Faster soldiers   
!time for bed       Kill selected units   
!mona lisa          Random item/effect1   
!let me down        Remove disguises   
!when all else fails... Display programmer message   
!vic fontaine       Display programmer message   
!captain scarlet    Invincibility for all units   
!only human         Invincibility disabled  
!here's a lockpick... Small gun (use unknown) in item box   
!penny              Small gun (use unknown) in item box   

Thanks to Revolution reader matt ziemianski!