Dragon Ball Z: Sagas cheats and cheat codes for Gamecube

Cheat mode
Go to the options screen and press the following button combinations:
Up, Down, Up, Down, A, Start, X, Start, Y, A, Y, A, X, X, B

Get All Upgrades
Go to the Controller Menu in the Pause menu and enter UP, LEFT, DOWN, RIGHT, 
START, START, Y, A, X, B.

Invincibility
Go to the Controller Menu in the Pause menu and enter DOWN, A, UP, Y, START, 
START, RIGHT, LEFT, X, B

Goku's finishing move
Hit Y(5 times).

Bonuses:
Finish the game under any difficulty setting to unlock:
Broly Hidden Forms
Gohan Hidden Forms
Goku Hidden Forms
Krillin Hidden Forms
Tien Hidden Forms
Trunks Hidden Forms
Vegeta Hidden Forms
Yamcha Hidden Forms

Unlock Pendulum Room mode:
Finish the entire game once