This method is great for testing intersections with an X,Y point of the stage. Ideally you would use this with small objects to allow for a more realistic hit test.

I used my circle class from earlier.

package {
     import flash.display.Sprite;  

     public class Circle extends Sprite {
        private var radius:Number;
        private var color:uint;

		private var xcircle:Number;
		private var ycircle:Number;

		public function Circle(radius:Number=20, color:uint=0x336699, xcircle:Number = 10, ycircle:Number = 20) {
			this.x = xcircle;
            this.y = ycircle;
			this.radius = radius;
			this.color = color;

            draw();
		}

		public function draw(){
			graphics.beginFill(color);
            graphics.drawCircle(0, 0, radius);
            graphics.endFill();
		}
	}
}

Now my document class for the hitTestObject method

package {
     import flash.display.Sprite;
	 import flash.events.Event;

     public class HitTestPoint extends Sprite {
		private var circle:Circle;
		private var circle2:Circle;

		private var radius:Number;
		private var color:uint;

		private var xcircle:Number;
		private var ycircle:Number;

		public function HitTestPoint(){
			init()
		}

		public function init(){
			// CIRCLE 1
			// draw the first circle and center it on the stage
			circle = new Circle(30,0x333333,stage.stageWidth/2, stage.stageHeight/2);
			// display the circle
			addChild(circle);
			circle.startDrag(true);

			// CIRCLE 2
			circle2 = new Circle(4,0x000000,200,200);
			// display the circle
			addChild(circle2);
			circle2.alpha = 10;

			// create the listeners
			addEventListener(Event.ENTER_FRAME, testHit);
		}

		private function testHit(e:Event):void
		{
			// hit point area is x = 200 and y = 200
			if(circle.hitTestPoint(200, 200, false))
				trace ("HIT !!!!");
		}
	}
}

To start I used this Circle.as file for my circle class

package {
     import flash.display.Sprite;  

     public class Circle extends Sprite {
        private var radius:Number;
        private var color:uint;

		private var xcircle:Number;
		private var ycircle:Number;

		public function Circle(radius:Number=20, color:uint=0x336699, xcircle:Number = 10, ycircle:Number = 20) {
			this.x = xcircle;
            this.y = ycircle;
			this.radius = radius;
			this.color = color;

            draw();
		}

		public function draw(){
			graphics.beginFill(color);
            graphics.drawCircle(0, 0, radius);
            graphics.endFill();
		}
	}
}

… and here is the document class:

package {
     import flash.display.Sprite;

	 import flash.events.Event;
	 import flash.events.MouseEvent;

     public class HitTest extends Sprite {
		private var circleOne:Circle;
		private var circleTwo:Circle;

		private var radius:Number;
		private var color:uint;

		private var xcircle:Number;
		private var ycircle:Number;

		public function HitTest(){
			init()
		}

		public function init(){
			// CIRCLE 1
			// draw the first circle and center it on the stage
			circleOne = new Circle(30,0x333333,stage.stageWidth/2, stage.stageHeight/2);
			// display the circle
			addChild(circleOne);

			// CIRCLE 2
			// draw the second circle and put in the top left corner
			circleTwo = new Circle(20,0x123456,20,20);
			// display the circle
			addChild(circleTwo);
			// make it draggable
			circleTwo.startDrag(true);

			// LISTENERS

			// create the listeners
			stage.addEventListener(MouseEvent.MOUSE_DOWN, testHit);
		}

		private function testHit(m:MouseEvent):void
		{
			if(circleTwo.hitTestObject(circleOne))
				trace ("HIT !!!!");
		}
	}
}

To run the files, all you need to do is drag the one circle and then left click to determine if the two objects are colliding