To activate the cheat mode (an "Extras" menu), type 
CTRL A O D B A M F 
in sequence at end turn. The menu contains the following cheats:

          ScaleIt       : Increases your production. 
          ArmyInfo      : See information about the other races. 
          MoneyAndPower : self-explanatory. 
          AllSeeingEye  : Reveal the whole map! 
          GetRichQuick  : self-explanatory. 
          GetSmartQuick : self-explanatory. 
          MissileCrisis : Creates the production of nuclear missiles. 
          SettlersHo!   : Creates settlers. 
          Nukestorms    : Causes Global Warming. 
          Automode      : The computer moves for you. 
          Armaggedon    : Nukes the whole world!

(Submitted by Rob Loach - rob@loacheng.on.ca)