import flash.events.MouseEvent;
import flash.geom.ColorTransform;

circulo_mc.addEventListener(MouseEvent.ROLL_OVER, over);
circulo_mc.addEventListener(MouseEvent.ROLL_OUT, out);

function over(e:MouseEvent){

var cambiarColor:ColorTransform = new ColorTransform();
cambiarColor.color = 0x442288;
circulo_mc.transform.colorTransform = cambiarColor;

}

function out(e:MouseEvent){

var cambiarColor:ColorTransform = new ColorTransform();
cambiarColor.color = 0x994433;
circulo_mc.transform.colorTransform = cambiarColor;

}