Enter this code at the screen that says: PRESS START

Bonus Match-Up option
O,Up,up,down,down,left,right,left,right

Enter this code at the PRESS START screen or whilst paused
Play as Ned Flanders: O,left,up,left,down,L2
Play as Moe: O,left,up,left,down,L1
Play as Bumble Bee man: O,left,up,left,down,R1
Play as professor fink: O,left,up,left,down,R2
gain another ring: O,R2,R1,O,R2,R1
big arms,L1,O,L1,O,R1,O,R1

Enter while playing a match:
(note: it will ask you to save, and press yes. my friend told me this code and i dont know if it works)
get Mayor Quimby:R1,R1,R1,/\.
then go to the character screen and he should be there

don't know if these codes work, test them your sefl at start screen or whilke pausing a match:
big ape: O,L1,O,R1,O,L2,O,R2
super characteronly while paused) X,square,square,select,O,start

instead of unlocking it the long way or hard way
just chuck this code in at the press start screen press the following bottons upx2 downx2 left right the words bonus mach up will appear u wiil play as itchy & scrachy,kodos & kang Mr burns and smithers and so on note:x2 indicates press twice

Mega Arm Mode:
During gameplay press pause and enter the following:
circle, L1, circle, R1, circle, L2, circle

Extra Ring:
During gameplay press pause and enter the following:
circle, R2, R1, circle, R2, R1

Unlock Hidden Wrestlers:
Finish the game under all 3 modes and you will unlock additional characters as wrestlers.