[Tato]

DragManager посмотрите документацию, Я быстро разобрался.

private var img:Image = new Image();
....
			protected function drag_fun(event:MouseEvent):void
			{
				var dragInitiator:Image=Image(event.currentTarget);
				var ds:DragSource = new DragSource();
 
				ds.addData(dragInitiator, "img");				
				img.source = dragim;
				img.width = 51;
				img.height = 60;
				img.alpha = .9;	
				DragManager.doDrag(dragInitiator, ds, event, img);
			}

protected function DragEnter(event:DragEvent):void
{
	if (event.dragSource.hasFormat("img")){
		DragManager.acceptDragDrop(myHBox)
}