how to retrieve value <blip:user>jetset</blip:user>in xml ?

<rss>
<item>
<guid isPermaLink="false">53A9C6E6-ECE8-11DD-8BD8-CA3B94C006BC</guid>
<link>http://blip.tv/file/1710703</link>
<title>and the oscar goes to...</title>
<blip:user>jetset</blip:user>
<blip:userid>33980</blip:userid>
<blip:safeusername>epicfu</blip:safeusername>
</item>
</rss>

function loadxml(success:Boolean){
    
    var nodes = xml.firstChild.childNodes[0].childNodes;
    var total = nodes.length;
    trace(total);
    
    if(success){
        for (var i:Number = 0; i<total; i++) {
            trace(i);trace(nodes[i].childNodes[3].localName);
                        // output -
        }
    }else{
        trace('fail!');
    }
}