[scarbo]

var mySound:Sound = new Sound(sound_target);
mySound.attachSound('my_sound');
mySound.start();
mySound.setVolume(0);
sound_target.onEnterFrame = volume_plus;
var interval:Number = 0.5;
//
function volume_plus() {
	if (mySound.getVolume()>=100) {
		delete this.onEnterFrame;
	}
	mySound.setVolume(mySound.getVolume()+interval);
}