Livestream

Here's an example taken from the as3 language reference library from the above link to get started, likely you'll have to use rtmp streaming with livestream...

package {

    import flash.display.Sprite;

    import flash.events.NetStatusEvent;

    import flash.events.SecurityErrorEvent;

    import flash.media.Video;

    import flash.net.NetConnection;

    import flash.net.NetStream;

    import flash.events.Event;

    public class NetConnectionExample extends Sprite {

        private var videoURL:String = "http://www.helpexamples.com/flash/video/cuepoints.flv";

        private var connection:NetConnection;

        private var stream:NetStream;

        private var video:Video = new Video();       

        public function NetConnectionExample() {

            connection = new NetConnection();

            connection.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);

            connection.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityErrorHandler);

            connection.connect(null);

        }

        private function netStatusHandler(event:NetStatusEvent):void {

            switch (event.info.code) {

                case "NetConnection.Connect.Success":

                    connectStream();

                    break;

                case "NetStream.Play.StreamNotFound":

                    trace("Stream not found: " + videoURL);

                    break;

            }

        }

        private function securityErrorHandler(event:SecurityErrorEvent):void {

            trace("securityErrorHandler: " + event);

        }

        private function connectStream():void {

            addChild(video);

            var stream:NetStream = new NetStream(connection);

            stream.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler);

            stream.client = new CustomClient();

            video.attachNetStream(stream);

            stream.play(videoURL);

        }

    }

}

class CustomClient {

    public function onMetaData(info:Object):void {

        trace("metadata: duration=" + info.duration + " width=" + info.width + " height=" + info.height + " framerate=" + info.framerate);

    }

    public function onCuePoint(info:Object):void {

        trace("cuepoint: time=" + info.time + " name=" + info.name + " type=" + info.type);

    }

}