Rockstar Toronto have confirmed that patch 1.0.3.0 is now available for the PC version of Grand Theft Auto IV. To download, sign into Windows LIVE next time you play the game and you'll be prompted to download. Manual install links will be up shortly. Below is a summary of what the patch includes.

GRAPHICS:

Interior Lights for ATI 1900 series cards

- All light sources appear for users with 1900 series ATI cards. (ie. Pool Mini Game)

- ALT-TAB fixed

Graphics Settings

- Added menu option "OFF" for Reflection quality

- Added menu option "OFF" for Shadow quality

PERFORMANCE:

- Physics optimizations to improve situations with heavy physics calculations (ie. 32 player races)

- Graphical Performance Optimizations

MULTIPLAYER:

NAT Type detection

- Detect if user has a "strict" NAT and displays message for user

Voice chat is received even if your microphone is turned off

CONTROLS:

Keyboard/Mouse

- Remapping restrictions removed

- Allow Enter, Backspace, and Arrow keys to be remapped by user

- Allow multiple mouse buttons to be mapped

Enable/Disable DirectInput in Menu

- Users can now activate/deactivate Direct Input devices from "Controls" menu.

- If commandline "-usedirectinput" is active, it will override pause menu setting

Use 2 direct input devices simultaneously (ie. Wheel and Gamepad)

- Users can now use 2 different controllers at once, including 1 XInput and 1 Direct Input device

Added more Direct Input / XInput device support

- Saitek P380/P480/P580/P990

- Saitek PS1000/PS2700/P3200/P3600

- Gravis Eliminator Shock gamepad

SECURITY:

Detect modified files and prevent users from entering multiplayer if found

- Game will prompt with a message after blocking user with modified data files from entering multiplayer

- Should prevent multiplayer access from cell phone and GFWL join in progress

VIDEO EDITOR:

Scroll Bar improved response

- Tweaked to respond better to keyboard inputs

Sped up load times for users with many clips

TITLE UPDATE 2 FIXES:

Return of Hot Dog Stands and other props

- Missing hot dog vendors, fences, gates, pylons should be present throughout the world

Scrolling signboards

- Activate missing scrolling signboard text (ie. highway signs, Star Junction, Clock Tower Sign)

ALT-TAB pauses game during cutscenes

- Cutscenes should now pause and resume correctly after an ALT-TAB task switch. Audio remains in sync

GENERAL ADDITIONS/FIXES:

Mismatched MODO/Perseus Clothing

- Fixed a bug when Niko mixes clothing from Perseus and Modo

360 Controller Texture

- Controller image should be visible in Controller Configuration screen

You may have spotted that R* has now added detection for modders in multiplayer, hopefully this should provide massive improvements for those of you affected by people cheating their way through multiplayer matches.

Link: Patch 1.0.3.0, Download mirror