On the title screen, (where the family is watching the TV together) type "COWABUNGA" for unlimited lives.
Type "EAT MY SHORTS" you can now skip levels with the number keys or the 'F' key.
Try typing "SHEEP IN A GROUP WEARING HATS" at some point for infinite lives.
When you have the whistle, stand by the last window of the Springfield Retirement Home and blow it. Now a guy should appear and start throwing lots of money at you, so grab it and go on a shopping spree!