private var urlLoader:URLLoader;
private var loadedXML:XML;

urlLoader = new URLLoader();
urlLoader.addEventListener(Event.COMPLETE,fileLoadedHandler);
urlLoader.load(new URLRequest("myTestFile.xml"));

private function fileLoadedHandler(event:Event):void
{
    loadedXML:XML = new XML(urlLoader.content);
    // loadedXML..region returns an XMLList of all region nodes
        // loadedXML..station returns an XMLList of all station nodes
}