You can add event listeners to a movie clip, sprite, etc, to make it behave more like a button, so that you can change its look when mousing over it.
Download the FLA filemyShape_mc.addEventListener(MouseEvent.MOUSE_OVER, mouseover);
myShape_mc.addEventListener(MouseEvent.MOUSE_OUT, mouseout);
function mouseover(myEvent:MouseEvent)
{
myShape_mc.scaleX = 1.1;
myShape_mc.scaleY = 1.1;
myShape_mc.blendMode = "overlay";
}
function mouseout(myEvent:MouseEvent)
{
myShape_mc.scaleX = 1;
myShape_mc.scaleY = 1;
myShape_mc.blendMode = "normal";
}