L2,R2,<,>,and the left analog stick all control the fast forward or rewind
the right analog stick gives you precision fast forwarding or rewinding.
L1 skips back a scene
R1 skips ahead a scene
Triangle brings up the menu
Circle quits playback or exits a menu
square usually doesn't do anything. Used to resize video but I dont know if it does anymore
X pauses the video or selects something in a menu
Anything you want to do that is not listed here is in the Triangle menu.
(actually, i think Square might bring up the pop-up menu on blu-ray movies. not sure if DVD's have these kinds of menus)