Just saw that the ASP.NET team released ASP.NET AJAX 1.0 and have updated the website...

ASP.NET AJAX is a free framework for quickly creating a new generation of more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers.

With ASP.NET AJAX, you can:

  • Create next-generation interfaces with reusable AJAX components.
  • Enhance existing Web pages using powerful AJAX controls with support for all modern browsers.
  • Continue using Visual Studio 2005 to take your ASP.NET 2.0 sites to the next level.
  • Access remote services and data directly from the browser without writing a ton of complicated script.
  • Enjoy the benefits of a free framework with 24x7 technical support provided by Microsoft.

Download ASP.NET AJAX v1.0

Source: AJAX : The Official Microsoft ASP.NET AJAX Site