I have used XPath before, recently when I needed I forgot the syntax, so thought of keep it written here. It may come helpful for some others as well
var xml:XML = new XML();
xml.ignoreWhite = true;
xml.onLoad = function()
var thumbs:Array = XPathAPI.selectNodeList(this.firstChild, “/rss/channel/item/media:thumbnail”);
for(var i in thumbs)
This tutorial was a great help.