Microsoft released ASP.NET AJAX
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 technical support provided by Microsoft.
You can download ASP.NET AJAX here: http://ajax.asp.net/downloads/default.aspx?tabid=47