This is cool news. AJAX 1.0 Beta is no more. Its now in Release Candidate mode. Wow. And it seems like there wont be any major change between this RC and the Final Release which would also come in sooner or later. This installer would contain the core extensions. And there is also a December CTP release of the additional ASP.NET AJAX features. So congratulations to all of those AJAX controls that made it into the System.Web namespace. 
Here’s where you can get your hands on it. Have fun.
Extensions Setup:
http://www.microsoft.com/downloads/details.aspx?FamilyId=8FA6E076-582B-440F-95CB-C40ED23FDF59&displaylang=en
Additional Features:
http://www.microsoft.com/downloads/details.aspx?FamilyId=29B6B62B-A25A-498D-AA14-90B68CF2E392&displaylang=en
