MACROMEDIA FLASH MX 2004-ACTIONSCRIPT LANGUAGE Reference page 630

var loaded_interval:Number = setInterval(checkBytesLoaded, 500, stream_ns);
function checkBytesLoaded(my_ns:NetStream) {
var pctLoaded:Number = Math.round(my_ns.bytesLoaded/my_ns.bytesTotal*100);
loaded_txt.text = Math.round(my_ns.bytesLoaded/1000)+" of
"+Math.round(my_ns.bytesTotal/1000)+" KB loaded ("+pctLoaded+"%)";
progressBar_mc.bar_mc._xscale = pctLoaded;
if (pctLoaded>=100) {
clearInterval(loaded_interval);
}
}
See also
NetStream.bufferLength
630 Chapter 2: ActionScript Language Reference