Like Zanzibar, I was involved with the making of TPM (I helped program the cheats, etc.). Here are a few cheats that (as far as I know) haven't been released. I inputed these by myself, and I don't think many people knew about them.
'Skywalker': Allows player to walk over air.
'Cantina Song': When entered in the Mos Espa Cantina, the music is replaced with the "Star Wars Cantina" parody song by some guy (I forget his name). This one is extremely illegal, and I'm the only one who knew this, until now.
'Let There Be Light': Gives Panaka and Amidala lightsabers.
T = Triangle
C = Circle
X = X
S = Square
Pause game, highlight 'Weapons', and press:
SCTXXTCS 'Select' = All Weapons, Infinite Ammo
Highlight 'Items' and press:
XTCSSCTX 'Select' = Secret menu, allowing you to play as any character (Obi-Wan, Qui-Gon, Panaka or Amidala)
That's all for now.