1) First make sure that the security level in IIS (at least for the WebOrb virtual Directory is set to Windows Integrated security)

2) CREATE A C# CLASS with the following function

public string getUsername()
{

System.Security.Principal

.WindowsPrincipal p = System.Threading.Thread.CurrentPrincipal as System.Security.Principal.WindowsPrincipal;
string strName = p.Identity.Name;
return strName;
}

Flex Client Code Action Script

<mx:Script>
<![CDATA[
import mx.rpc.events.ResultEvent;

//import mx.rpc.remoting.RemoteObject;
import flash.net.registerClassAlias;
import mx.controls.Alert;
import mx.messaging.config.ServerConfig;
private var nc:NetConnection;
private var so:SharedObject;

private function establishConnection():void
{

var ro:RemoteObject = new RemoteObject();
ro.destination = "PANO2";
ro.addEventListener(ResultEvent.RESULT, dataHandler);
ro.getUsername();

}
private function dataHandler( event:ResultEvent ):void
{
var uname:String = new String();
uname = event.result.toString();
//At this point you have uname as a string. Do what you want with it.
}

]]>

Greg FLEX, WEBORB