Today sees the release of the first ASP.NET AJAX beta after a series of ASP.NET Atlas CTP releases. This also means that ASP.NET AJAX has split into separate "core" and "additional" features for the 1.0 release. If you've been to any of my recent presentations on ASP.NET AJAX you'll have heard me explain that the "core" features will become a fully supported Microsoft product at v1.0 (ie you can get support from Product Support Services, they follow our standard support lifecycle etc). The "additional" features are an optional download that bridge the gap between the "core" feature set and the features that you've become used to in the CTPs to date. For more details see the feature matrix ("Feature Matrix" tab) and Scott Guthrie's original blog post "Atlas" 1.0 Naming and Roadmap".
There is a comprehensive whitepaper describing the changes between CTP and v1.0 Beta releases and also a migration guide for those of you who've built ASP.NET AJAX sites with the CTPs. Documentation has also been updated. As has the Control Toolkit.
Wow - that's a lot of stuff for a Friday. And as I have to deliver a couple of sessions on this next week, I'd better start trying to get my head around it!