What is the ASP.NET Ajax Framework? What versions have been released so far?

ASP.NET AJAX is a free framework to implement Ajax in asp.net web applications, for quickly creating efficient and interactive Web applications that work across all popular browsers.
The Ajax Framework is powered with
1 – Reusable Ajax Controls
2 – Support for all modern browsers
3 – Access remote services and data from the browser without tons of complicated script. Versions of Ajax release
1 – ASP.NET Ajax Framework 1.0 (earlier release to this was called the Atlas)
2 – ASP.NET Ajax Framework 1.0 was available as a separate download for ASP.NET 2.0