What is the theory behind the pinch zoom in and out technique used on the iPhone?? How would one do this? Do you get the distance between 2 touch points and measure them? can someone point me in the right direction :)

Thanks :P

Here is the end code, it works for zooming in and out as well as moving around the iPhone, good usage in IOS games

//Author DOMINIC OBOJKOVITS
var check : boolean = false;
var OPinchDist : float;
var currentDist : float;
var counter : float ;
var touchP : Vector2;
var thing : Transform;
var speed : float = 0.1;
var Osize : float;

function Start(){

    iPhoneKeyboard.autorotateToPortrait = false; 
    iPhoneKeyboard.autorotateToPortraitUpsideDown = false; 
    iPhoneKeyboard.autorotateToLandscapeRight = false; 
    iPhoneKeyboard.autorotateToLandscapeLeft = false;

}

function Update () {

    var count = Input.touchCount;

    //Limits
    Osize = Camera.main.orthographicSize;
    if (Osize >= 12){
        Osize = 12;    
    }
    if (Osize <= 4){
        Osize = 4; 
    } 
    speed = 0.05 * (Osize/5);

    //Zooming Factor
    if (count >= 2){

       if (check == false){
         OPinchDist = Vector2.Distance(Input.GetTouch(0).position,Input.GetTouch(1).position);
         check = true;
       }
       currentDist = Vector2.Distance(Input.GetTouch(0).position,Input.GetTouch(1).position);
       var zoomFactor = ( (OPinchDist) / (currentDist) );

       Camera.main.orthographicSize = Osize * zoomFactor;

    }
    if (count <= 1){
       check = false;    
    }

    //Moves the camera around
     if (Input.touchCount == 1 && 
      Input.GetTouch(0).phase == TouchPhase.Moved) {
        var touchDeltaPosition:Vector2 = Input.GetTouch(0).deltaPosition;
        thing.Translate (-touchDeltaPosition.x * speed,-touchDeltaPosition.y * speed, 0);
    }


}