3D GTA style aiming and camera movement

[JAA]

I want the camera to be controlled like it is in any 3D GTA for the PC. Where the mouse pointer stays in the center of the screen and when you move the mouse side to side and up and down the camera moves accordingly. I know the same thing happens in Alice when you have the following event:
Allow mouse to control [camera]
...but it only works when the mouse is clicked down. Also, I made a world where when the mouse isn't at the center of the screen the camera turns but this isn't really what I'm looking for because the mouse doesn't stay centered.
Can someone show me how to make a world where the mouse controls the camera and cross hairs like it does in GTA?

Here's a thread where I attached my closest solution.
http://alice.org/community/showthread.php?t=4729