When in "[CTRL] + 0" mode, click on an enemy unit and press delete. The unit is destroyed just like your own units are when you press delete.
Double Unit
Remove a unit carrier at the same time it explodes and that unit will be doubled now.
Faster patient walking
Click on "Release Patient" when an Imperial vehicle is being healed on the repair bay. It will walk away faster.
Hitting air units from the ground
Ground units cannot normally hit air units. However, an AT-AT's chin gun can hit an enemy air unit.
Level select
Note: The v1.1 patch is required for this code. Start a new game and enter "TheWorldIsYours" as a case-sensitive name in the New Player slot. Note: When choosing your new player you must double-click on the name, and not click on the blue arrow.
Pod Racer appearance
Complete the second objective in the third training mission (destroy the buildings at the Jawa camp) and two Pod Racers will start racing around.
Special Troops
First of all, you MUST have the version 1.1 patch in order for this to work. Then create a new file called "TheGalaxyIsYours" and capitalization does count! Enter any mission (even a skirmish) and press Ctrl+0 and at the bottom of the screen it should say "stormtrooper". Press up or down until you find the unit you want (I've gotten Darth Vader, snowtroopers, and 4 different Lukes!). Then press left to get what you chose. If you think your guys are weak, just press Num lock+Keypad asterik (*) to get 999,999 (!) life for your selected unit.
Unlimited Command Points
At the Select Player screen, create a new player named TheGalaxyIsYours. Then, during gameplay, press M to get 500 command points. You can press M as much as necessary.