Visual Studio 2005 provides an Web site application template to create AJAX enabled ASP.NET Web sites.

However, when you use Visual Studio 2008, you will not find this template in the New Web site creation templates.  The reason for this is that  Visual Studio 2008, by default creates a .NET Framework 3.5 application.  See the .NET Framework type at the top right section of the window image below.

AJAX is now integrated into the framework.  In Visual Studio 2008 all web sites that are created using .NET Framework 3.5 are AJAX enabled.  You don’t have to create a separate AJAX enabled web pages.