I wanted to do a 3d FPS and found a few stand alone iwads that run on the ps3 doom engine.
fallout (doom2.wad) doomwadstation.com/main/fallout.html
ultimate freedoom (doom.wad) nongnu.org/freedoom/index.html
Chex Quest (doom1.wad) doom.wikia.com/wiki/Chex_Quest
FREEDOOM ONLY WORKS WHEN STARTED FROM EPISODE 2 AND CRASHES RANDOMLY.
damn nice control system, good replay value, no music or jump button. but all in all very cool.
Also you will need to back up any wads if you already have doom installed.