Grand Theft Auto IV Guide - PlayStation 3 Controls

In Vehicle Controls

L1 Button - Fire Weapon
L2 Button - Brake/Reverse
R1 Button - Handbrake
R2 Button - Accelerate

Left Stick - Steering
Right Stick - Rotate Camera/Aiming
Left Stick Button - Horn/Engage Slow Motion (while in Cinematic Camera)
Right Stick Button - Look behind

Triangle Button - Exit Vehicle
Circle Button - Cinematic Camera/Mobile Phone Back/Hangup
X Button - Handbrake/Mobile Phone Forward/Answer
Square Button - Change Weapon/(Hold) Headlights

D-pad UP - Mobile Phone Up/Use Mobile Phone
D-pad RIGHT - Next Radio Station/(Hold) Turn Radio On/Off
D-pad DOWN - Mobile Phone Down/Skip Mobile Conversation/Zoom Out Mini-Map
D-pad LEFT - Previous Radio Station/(Hold) Turn Radio On/Off

Select Button - Cycle Camera Modes
Start Button - Pause Menu

On Foot Controls

L1 Button - Pick Up/Context
L2 Button - Target Lock On/(Half Hold) Free Aim
R1 Button - Enter/Exit Cover
R2 Button - Fire Weapon/(Half Hold) Free Aim

Left Stick - Movement
Right Stick - Rotate Camera/Switch Targets
Left Stick Button - Crouch
Right Stick Button - Look behind/Zoom Aim (when targeting)

Triangle Button - Enter Vehicle/Mount Ladder/Melee (Alternative Punch/Counter)
Circle Button - Reload Weapon/Mobile Phone Back/Hangup/Melee (Punch/Counter)
X Button - (Hold) Run/(Tap) Sprint/Mobile Phone Forward/Answer/Melee (Block/Dodge)
Square Button - Jump/Climb/Melee (Kick)

D-pad UP - Mobile Phone Up/Use Mobile Phone
D-pad RIGHT - Next Weapon
D-pad DOWN - Mobile Phone Down/Skip Mobile Conversation/Zoom Out Mini-Map
D-pad LEFT - Previous Weapon

Select Button - Cycle Camera Modes
Start Button - Pause Menu