... from a post by Scott Guthrie where he also estimates the v1.0 release "around the end of this year."
1) The client-side “Atlas” javascript library is going to be called the Microsoft AJAX Library. This will work with any browser, and also support any backend web server (read these blog posts to see how to run it on PHP and ColdFusion).
2) The server-side “Atlas” functionality that nicely integrates with ASP.NET will be called the ASP.NET 2.0 AJAX Extensions. As part of this change the tag prefix for the “Atlas” controls will change from <atlas:>to <asp:>. These controls will also be built-in to ASP.NET vNext.
3) The “Atlas” Control Toolkit today is a set of free, shared source controls and components that help you get the most value from the ASP.NET AJAX Extensions. Going forward, the name of the project will change to be the ASP.NET AJAX Control Toolkit.