Tinting with AS3

import fl.motion.Color;  
//create a Color object  
var c:Color=new Color();  
//set the color of the tint and set the multiplier  
c.setTint(0xff0000, 0.8);  
//apply the tint to the colorTransform property of  
//the desired MovieClip/DisplayObject  
mc.transform.colorTransform=c; //mc is a MovieClip  

Source:
http://www.cainmedia.com/articles/9/tinting-with-actionscript-3/