you can use the same actionscript 3.0 scripts in the flash source files in the RED5 tutorials for flex also to connect to RED5 server.

Thanks for your Reply Marx .
Red 5 Tutorial is working .But if i run the port tester in sample application it says connection rejected for default and 1943 for others its fails what i have to do.And I need to create a chat application in flex3.Can u explain me in detail how to connect the red 5 or can u send some samples am new to both red5 and Flex 3.

connection rejected means that you are not able to connect to server or the application is not able to load properly on server due to an error in application files on server or some other reason.

port testing application tries to connect to RED5 server from your system. The other reason can be firewall which has blocked the ports. Also check the address of the RED5 server to which you are trying to connect.

check the following samples to create basic application between flex and RED5

http://sunil-gupta.blogspot.com/2010/09/cool-new-flex-chat-component-with-red5.html

http://osdir.com/ml/web.flash.red5/2006-11/msg00458.html

http://robsilverton.wordpress.com/2008/12/04/basic-sharedobject-example-in-flex-red5-flash-media-server/

http://www.red5tutorials.net/index.php/Tutorials:Red5_and_Flex_2_on_Windows_XP

http://mswallace.com/2008/09/30/red5-and-flex-basics-part-1-keep-track-of-users/

private function Publisher():void{

var camera1:Camera = Camera.getCamera();
var video:Video = new Video(285, 254);
if (camera1)
{
video.attachCamera(camera1);
VideoDisplay1.addChild(video);
camera1.addEventListener(ActivityEvent.ACTIVITY, camera_activity);
camera1.addEventListener(StatusEvent.STATUS, camera_status);
}

var nc:NetConnection = new NetConnection();
nc.connect("rtmp://po9nawn4.rtmphost.com/Application");
nc.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);

function netStatusHandler(event:NetStatusEvent):void {
switch (event.info.code) {
case "NetConnection.Connect.Success":
var ns:NetStream = new NetStream(nc);
ns.attachCamera(camera1);
ns.publish("test", "live");
break;
case "NetStream.Play.StreamNotFound":
trace("Unable to locate video: ");
break;
}
}

}