StarCraft: Brood War
PC
Press Enter and type: 
black sheep wall                Shows entire map 
breathe deep                    Free vespene gas
food for thought                Ability to build units beyond the supply limit
game over man                   Makes you lose (useful?)
medieval man                    Gives free upgrades to units
modify the phase variance       Ability to build any building regardless of requirements
noglues                         Enemy can't use magic 
operation cwal                  Speeds up building and upgrading time
ophelia                         Type ophelia then press enter, then type in any mission name 
                                to warp
power overwhelming         	God Mode
radio free zerg			Play secret Zerg song
show me the money               Gives you 10,000 mineral and gas points 
something for nothing           Gives all available upgrades
staying alive                   You will not be able to complete the mission you are on
the gathering                   Unlimited casting ability
there is no cow level           Completes the mission you are on
war aint what it used to be     Disables fog of war
whats mine is mine              Free minerals
Secret Level:
Beat Zerg level 9 (The Reckoning) in under 20 minutesto open up a secret Protoss level. However, the mission itself won't appear on the mission select screen for any side, so be sure and save at the start of the level to play it again.