Enable Resident Evil 2 characters:
At the Title screen, press Triangle, Triangle, X, X, Square, Circle, Square, Circle. You'll hear a sound to confirm. Now press L2 or R2 at the Character Select screen to pick Leon, Claire, or the zombie cop.
After beating the game, press L1 while selecting a track to unlock a new track.
Thanks to Revolution readers Matt Atwood and Jason Sommerfeld!