Pet Accessory Unlock Codes (Cat Collars & Colors):
Under game options, press the new Key icon to enter codes. Do not use the cheat prompt.
(Credit: The Sims 2 Forums for finding these first)

Cat Collar Black Dot:   
ZZZ11ZZZ9Q11Q91ZB1A

Cat Collar Black Smiley:   
EEGJ2YRQQZ1RQ9QHA64

Cat Collar Blue Bones:   
EEGJ2YRQZZARQ9QHA64

Cat Collar Blue Camo:   
ZZZ11ZZZHQ11Q91ZB1A

Cat Collar Blue Star:   
EEGJ2YRQQZ1IZ9QHA64

Cat Collar Green Flower:   
EEGJ2YRZQZAIQ9QHA64

Cat Collar Navy Hearts:   
EEGJ2YRZQZ1IQ9QHA64

Cat Collar Orange Diagonal:   
EEGJ2YRQQZAIQ9QHA64

Cat Collar Pink Vertical Stripes:   
EEGJ2YRQQQARQ9QHA64

Cat Collar White Paws:   
EEGJ2YRQQQ1RQ9QHA64

Cat Collar White Zebra Stripe:   
EEGJ2YRZZQ1IZ9QHA64

Blue Cats:   
EEGJ2YRQZZAIQ9QHA64

Deep Red Cats:   
EEGJ2YRQQQAIQ9QHA64

Goofy Cats:   
EEGJ2YRQZQ1IZ9QHA64

Green Cats:   
ZZZ11ZZZ9QA1Z91ZB1A

Light Green Cats:   
EEGJ2YRZZQ1RQ9QHA64

Neon Green Cats:   
ZZZ11ZZZHQA1Q91ZB1A

Neon Yellow Cats:   
EEGJ2YRZZQARQ9QHA64

Pink Cats:   
EEGJ2YRQZZ1IZ9QHA64

Purple Cats:   
EEGJ2YRQQZARQ9QHA64

Activating the in-game console:
To open up the console, hit the CTRL, SHIFT, and C keys all at once. Then type in the following cheats.

Makes pets fully controlable, but you can't cancel actions from their queue:
boolprop ControlPets [on/off]

Turns off aging for kittens and puppies:   
boolprop DisablePuppyKittenAging [true/false]

Activates labels in the detail view of each Buy mode and Build mode objects to show which product they came from (EP or SP):
boolprop ShowCatalogePFlags [true/false]

Turns pet free will off:   
boolprop PetsFreeWill [true/false]

Deletes all fences on lot:   
DeleteAllFences

Deletes all half walls on lot:   
DeleteAllHalfWalls

Deletes all walls on lot:   
DeleteAllWalls

Deletes all Doors, Windows or Stairs on lot:   
DeleteAllObjects [Doors/Windows/Stairs]

Makes the actions in a pet's queue accessible:
boolprop PetActionCancel [true/false]

Activates a tool to change the roof slopes of individual roofs on a lot    IndividualRoofSlopeAngle [15/75]:
,000    motherlode