Get mouse position on screen (from the center)

Hay, how do i get the mouse position on screen?

I can get mouse X, but it's in relation to the top left of the screen. I was the mouse position from the center of the screen. So the top left with be minus something, and the center will be 0.

var mousePos = Input.mousePosition;
mousePos.x -= Screen.width/2;
mousePos.y -= Screen.height/2;

You can also use the OnGUI callback function

	void OnGUI () {
    	Event currentEvent = Event.current;
    	if (currentEvent.isMouse) {
    		Vector2 mouseXY = new Vector2 (currentEvent.mousePosition.x - Screen.width/2, currentEvent.mousePosition.y - Screen.height/2);
			// AND DO THE REST
    	}
    	
    }

See also:

http://docs.unity3d.com/Documentation/ScriptReference/Event-current.html
http://docs.unity3d.com/Documentation/ScriptReference/Event-isMouse.html