Backing up Rick's comments, you may want to view this brief video:

How Do I: Add ASP.NET AJAX Features to an Existing Web Application?

http://asp.net/learn/videos/view.aspx?tabid=63&id=81



>Hi,
>
>I am intrigued by Microsoft’s asp.net ajax framework and would like to start adding some of it's functionality to my web applications. Are there any white papers on hooking the ajax framework into new and existing mm.net web forms?
>
>Regards,
>Neil Gorin