make user control(.ascx) for flash
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="WebUserControl.ascx.cs" Inherits="WebUserControl" %>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Scribblar Room</title>
<LINK href="http://media.muchosmedia.com/brainwave/style.css" rel="stylesheet" type="text/css">
<script type="text/javascript" src="http://media.muchosmedia.com/scribblar/scripts/includes.js"></script>
<script type="text/javascript">
var targetID = "scribblar";
var flashvars = {};
flashvars.userid = "0";
flashvars.username = "shiva";
flashvars.roomid = prompt("Enter Room Id");
flashvars.preferredLocales = "en_US";
var params = {};
params.allowscriptaccess = "always";
var attributes = {};
attributes.id = "scribblar";
attributes.name = "scribblar";
swfobject.embedSWF("http://media.muchosmedia.com/scribblar/v2/main.swf", "alternate", "80%", "80%", "10.2.0", "http://media.muchosmedia.com/swfobject/expressInstall.swf", flashvars, params, attributes);
</script>
</head>
<body scroll="no">
<div id="alternate">
<a href="http://www.adobe.com/go/getflashplayer">This page requires the latest version of Adobe Flash. Please download it now.<br>
<img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" border="0" alt="Get Adobe Flash Player" />
</a>
</div>
</body>
</html>
and add this control to aspx page
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Register src="WebUserControl.ascx" tagname="WebUserControl" tagprefix="uc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Scribblar Room</title>
<LINK href="http://media.muchosmedia.com/brainwave/style.css" rel="stylesheet" type="text/css">
<script type="text/javascript" src="http://media.muchosmedia.com/scribblar/scripts/includes.js"></script>
</head>
<body scroll="no">
<form id="form1" runat="server">
<div id="alternate">
<uc1:WebUserControl ID="WebUserControl1" runat="server" />
<a href="http://www.adobe.com/go/getflashplayer"><br>
</a></div>
<br />
<a href="javascript:location.reload(true)">Change RoomID</a>
</form>
</body>
</html>