Integrating AJAX into current site

I have seen many AJAX videos now that are good but they all start from a blank page.

I have sites I have built using ASP.NET 2 and I would like to implement ajax into those sites without rebuilding them.

Are there any videos/articles that show how to do this.

You don't have to rebuild a brand-new one. The point is to change Web.Config file. You can get template web.config file in C:\Program Files\Microsoft ASP.NET\ASP.NET 2.0 AJAX Extensions\v1.0.61025 (Beta 1 version) afterASP.NET AJAX v1.0 core Beta 1 release installed and then update web.config in your web application based on it. And you have to add some aspx source codes in your web pages, e.g. ScriptManager, UpdatePanel, etc.

Is ASP.NET Ajax compatible with ClientScriptManager CallBack functions?

The current project usesClientScriptManager CallBack functions to implement a simple callback scenario. Is it OK to add ASP.NET Ajax and use the both ASP.NET Ajax and ClientScriptManager CallBack on the same page?In Ajax,we will use ScriptManager.RegisterClientScriptResource?to register client script.Try to take a look at this link for details -http://ajax.asp.net/docs/mref/M_System_Web_UI_ScriptManager_RegisterClientScriptResource_3_2a609ef4.aspx