Unlimited power for all characters:
Enter this code while in the "Extras" menu: Circle, Left, Right, Circle, Square, L1
Unlock all Clichés:
Enter the code while in the "Extras" menu screen: Left, square, right, circle, right, L1
Unlock all Movies:
Enter the code while in the "Extras" menu: Square, Left, Square, Right, Circle, R1
All outfits and trophies for Marge:
While in the extras menu type in triangle, square, triangle, triangle, square, R3
Unlock Lisa's Outfits & Trophies:
To unlock all Lisa-related outfits and trophies, insert the following code while browsing the main menu: Square, Triangle, Square, Square, Square, L3 (click left analog stick).
Thanks to Revolution Readers Logan Teague and bladders!