Press [Alt]+[Backspace] during game play, then enter one of the cheats.

Result                        Code 
----------------------------------
2000 Electricity            - zap me
5000 Plastic                - fantastic plastic
Random team colors on map   - color me stupid
5 free paratroopers	    - ahoy captain dan
Increase the power	    - kick some butt
Stronger Tan units          - brainsick
Green troops invincible	    - don't touch me