hold L1 on the character select screen
For big feet, hands, legs and head, hold Down+X+Select while selecting your character. Don't release them until the fight begins.
Press and hold SELECT while choosing a Character. Release SELECT when the fight starts.
When playing in Vs. Mode, select Thok as your character. Now, here is the important part, at the VS screen press Down + X + Select + R2 and don't release until the fight starts. When the characters appear on the screen, Thok will be small. Now, as soon as you get a yellow power bar, press Down, Down, Down, Triangle and Thok will grow into his normal size, only he will have a HUMONGOUS head. Now you may think that you can just pull this code off by using the Big Head Mode, but his head is considerably bigger by doing the code listed above. Also, the code seems to make Thok fight better.
To access level select on VS Mode beat the game using Chewbacca.
Set the "Player Change at Continue" option to NO, then beat the game with Han Solo on the Jedi setting.
Set the "Player Change at Continue" option to NO, then beat the game with Luke Skywalker on the Standard or Jedi setting.
Play the survival mode and beat all 10 fighters to unlock Jodo Kast.
Press and hold L1 + L2 + R1 when you enter the team battle mode. Be sure the setting is on Jedi and the character change at continue option should be off. If done correctly the computer will automaticall select fighters for you and the words "Fight for Mara Jade" should be seen on the screen. Beat the computer then she will be at your control.
Set the "Player Change at Continue" option to NO, then beat the game with Princess Leia on the Jedi setting.
You can only do this in vs mode. Press and hold Down+Select+X+R2 keep holding until the fight starts.