[Krusty]

var volumeTransform:SoundTransform = new SoundTransform(1, 0);	
var slider:Slider = new Slider();
slider.liveDragging = true;
slider.maximum = 1;
slider.minimum = 0;
slider.tickInterval = 1;
slider.addEventListener(SliderEvent.CHANGE, on_SliderEvent_CHANGE );
private function on_SliderEvent_CHANGE (event:SliderEvent):void{
volumeTransform.volume = (event.target.value);
}

вроде того.