Normal Codes
(note these are done when your buttons are at their default setting,
 if not; G = X, A = Square, B = Triangle, K = 0) 

Bilstein: enter arcade mode, keep holding select, select gore,
          press G, K, G, K, A, A, A, B, B, B, press G+K

Kappah:   enter arcade mode, go to Gore, press select & keep it held,
          go to Hayato, press K, A, B, A, G, A, B, A, K, A, press G+B

Blood:    enter arcade mode, press select and hold it, go to Bilstein,
          press G, A, G, A, G, A, go to Kappah press K, B, K, B, K, B,
          then press L1 + R1 and let go of the select button.

(You can save these into the memory card)
                                                 
Dark Fighting: choose your character and hold; -down + L2 + R2- until
               the match starts.

Reset: R1 + L1 + select + start


Action Replay codes

P1 infinite health
801D7CA0  00C8
801D7CA2  00C8

Enable extra characters (bilstein/kappah/blood)
801EA8E4  0101
801EA8E6  0001