What I've learned from Miller @ Sanborn as "overcolor."
var ct:ColorTransform = new ColorTransform();
ct.color = 0xFFFFFF;
target_mc.transform.colorTransform = ct;

General use function
import fl.motion.Color;
import flash.geom.ColorTransform;
...
tintColor(mc2, 0x0000FF, .6);
...
function tintColor(mc:Sprite, colorNum:Number, alphaSet:Number):void {
  var cTint:Color = new Color();
  cTint.setTint(colorNum, alphaSet);
  mc.transform.colorTransform = cTint;
}
_ http://board.flashkit.com/board/showthread.php?t=764868