Press Right, Left, Down, Up, Right, Left, Down, Up, Start at the title screen.
Fight as Super Saiyanjin 4 Son Gokou:
Enable the "Bonus fighters" code, then press Triangle ten times, Square nine times at the title screen. For the Japanese version of the game, press Triangle five times, X nine times at the title screen.
Fight as Super Bebi:
Press Select, Square at the character select screen.
Wire frame fighters:
Select two player or training mode. Hold Select and press X when selecting a character to fight without texture mapping or shading.
Alternate costumes:
Select two player or training mode. Then, press Square + X + Circle when selecting a character.
Sound test:
Press L1, L2, R1, R2, Start at the title screen. Press Select after choosing a song to view the lyrics and additional song information. Press L1 + R1 + R2 + L2 at the presentation screen in the Japanese version of the game.
Using secret powers:
When playing as Gokuh (Normal DBGT), Vegeta (SSJ), Majin Boo and Gogeta or Vegetto, quickly press Forward, Back, Down, Up, Triangle (which releases the powers) during a match.
Gameshark Codes:
Invincible:
$865B79D0 5AE2
Full Energy:
$865B79CE 5916
*DragonBall Z: The Great DragonBall Legend*
999% in Z Campaign Mode:
Hold Select + Triangle + Square + X when the Z ranking screen is displayed at the end of an episode. Let go of the buttons, then press Up or Down to change the Z rank. Raise the Z rank to 999% to view the special ending.
*Dragonball Z Ultimate Battle 22*
Ultimate Battle 27 mode:
Press Up, Triangle, Down, X , Left, L1, Right, R1 at the title screen after the FMV sequence.
Another FMV sequence will be shown, followed by a title screen that now
says "Dragon Ball Z Ultimate Battle 27". Ultimate Battle 27 mode lets five more fighters to be available.
Gameshark Codes:
Invincible:
$8660C4AC 5AEA
$865F0550 5AEA
Full Energy:
$8660D74C 5B5A
$865F054E 5B5A
I got these codes at(go here it is an awsome site)