Controls - Xbox 360

Grand Theft Auto IV Guide - Xbox 360 Controls

In Vehicle Controls

Left Trigger - Brake/Reverse
Left Bumper - Fire Weapon
Right Trigger - Accelerate
Right Bumper - Handbrake

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

Y Button - Exit Vehicle
B Button - Cinematic Camera/Mobile Phone Back/Hangup
A Button - Handbrake/Mobile Phone Forward/Answer
X 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

Back Button - Cycle Camera Modes
Start Button - Pause Menu

On Foot Controls

Left Trigger - Target Lock On/(Half Hold) Free Aim
Left Bumper - Pick Up/Context
Right Trigger - Fire Weapon/(Half Hold) Free Aim
Right Bumper - Enter/Exit Cover

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

Y Button - Enter Vehicle/Mount Ladder/Melee (Alternative Punch/Counter)
B Button - Reload Weapon/Mobile Phone Back/Hangup/Melee (Punch/Counter)
A Button - (Hold) Run/(Tap) Sprint/Mobile Phone Forward/Answer/Melee (Block/Dodge)
X 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

Back Button - Cycle Camera Modes
Start Button - Pause Menu