As of today, Microsoft has officially released ASP.NET 2.0 AJAX Extensions to the web. This will be available under the Microsoft Reference License (Ms-RL).
ASP.NET AJAX 1.0 is a free framework for creating AJAX-enabled applications. Using the ASP.NET 2.0 AJAX Extensions you’ll be able to create interfaces and components that take advantage of the AJAX technology. All major browsers should support these interfaces and components.
You can download ASP.NET AJAX 1.0 from http://go.microsoft.com/fwlink/?LinkID=77296.
In addition to ASP.NET AJAX 1.0, you can also download the current release of the ASP.NET AJAX Control Toolkit. The toolkit lets you use a number pf code samples and components provided by Microsoft. You can also download the Microsoft AJAX Library, which contains a number of standards-based JavaScript classes that can be used with most of the current, major browsers.
For those that are adventurous, you can also download the ASP.NET AJAX Futures Community Technology Preview (CTP). This contains early releases of new AJAX features that Microsoft is working on.
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