2007-06-06 release of the AJAX Control Toolkit has a number of fixes identified as important by the community including designer support for Tabs and Web Services. It also has Animation support for some extenders, event support across the Toolkit, a Script combiner for reducing Toolkit scripts' download time, Dynamic context support for controls using Web Services, fixes to make ASP.NET Validators work with Toolkit extenders, Accessibility improvements and much more. See the release notes for more details.
AjaxControlToolkit.zip is the full release package with complete source code to all controls, the test framework, VSI, and more.
AjaxControlToolkit-NoSource.zip contains only the sample web site and VSI and is for people who don't need or want the source code for the controls.