ASP.NET "Atlas" is the codename for a set of technologies to add Ajax (Asynchronous JavaScript and XML) support to ASP.NET. It consists of a client-side script framework, server controls and more.

You can get more information on following pages:

ASP.NET "Atlas" Home Page - The main "Atlas" page

Installing the ASP.NET "Atlas" Web Site Template - Step-by-step instructions to help you download and install the Atlas Web Site Template, and to create your first Web site using it.

Installing the Hands-on Lab ASP.NET "Atlas" Web Site Template - Step-by-step instructions to help you download and install the Atlas hands-on lab.

"Microsoft gives first glimpse of Atlas" article on internetnews.com