Hold down CTRL at the main screen, and enter these codes:
Effect - Code
Complete the current research project - hditech
Add 100 to mall rating - hdirate
Toggle unlimited zoom - hdizooma
View Sim animation data - hdiart
Additional $100,000 - hdicash
All technology researched - hdilore
Lots of Easy money
To get loads of easy money, go to the Mall info screen. Then take out loads of loans to the limit (don't do this at the very begining of the game). When the limit has been reached, click the cross button to exit. Then notice the larger sum of money on hand. Go back to the Mall info screen to find that there are no Loans outstanding. Strangely this does not work all the time.