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Unfortunately Cocos2D does not support detecting standard gestures like pinch-to-zoom or two-finger-rotation by default, so one needed to develop own gesture-recognizers based on the coordinates you get by using CCStandardTouchDelegate. The good news is, that developer xemus has created a patch that adds support of Apple's UIGestureRecognizer to Cocos2D (as found in this forum discussion). Here is a short introduction on how to use this patch with Cocos2D 0.99.5-rc1.

• Download the patch from https://github.com/xemus/cocos2d-GestureRecognizers/archives/master
• Apply the patch using the Terminal:

cd <path-to-project>/libs/cocos2d 
patch -p1 -i cocos2d.patch

• You might get an error, saying Hunk #3 FAILED at 269. The solution is to go to line 276 of the file CCNode.m and add the following lines:

#ifdef __IPHONE_OS_VERSION_MAX_ALLOWED 
        // lazy allocation 
        gestureRecognizers_ = nil; 
        isTouchEnabled_ = NO; 
#endif

• Don't forget to add the files CCGestureRecognizer.h/.m to your XCode-Project, so that they will be compiled

That's all you need to get it running. Now you can use a new class named CCGestureRecognizer in your App like that:

// create a CCGestureRecognizer for rotation-gesture
CCGestureRecognizer* recognizer;
recognizer = [CCGestureRecognizer CCRecognizerWithRecognizerTargetAction:[[[UIRotationGestureRecognizer alloc]init] autorelease]    // use rotation recognizer
    target:self  // callback object -> this object gets called when there is rotation gesture
    action:@selector(rotateGesture:node:)];   // callback method -> rotateGesture:node: gets called when there is rotation gesture
[self addGestureRecognizer:recognizer]; // register the gesture recognizer

// create a CCGestureRecognizer for pinch-gesture
recognizer = [CCGestureRecognizer CCRecognizerWithRecognizerTargetAction:[[[UIPinchGestureRecognizer alloc]init] autorelease]    // use rotation recognizer
    target:self // callback object
    action:@selector(pinchGesture:node:)];  // callback method
[self addGestureRecognizer:recognizer]; // register the gesture recognizer

Implement your callback-methods that will receive the gesture-events. This sample codes will change the rotation and scale of a sprite.

// This method is called upon recognizing a gesture by the UIRotationGestureRecognizer
- (void)rotateGesture:(UIRotationGestureRecognizer *)recognizer node:(CCNode *)node {
    // get the rotation from the recognizer, convert it into degrees and set it to the sprite's rotation
    sprite.rotation = CC_RADIANS_TO_DEGREES([recognizer rotation]);
}

// This method is called upon recognizing a gesture by the UIPinchGestureRecognizer
- (void)pinchGesture:(UIPinchGestureRecognizer *)recognizer node:(CCNode *)node {
    // get the scale from the recognizer
    sprite.scale = [recognizer scale];
}

You can download a full documented sample-project and have a look in the TouchLayer.m file: Cocos2DTouch.zip