Last week I had to help someone out on the ASP.NET that was asking the question that he couldn't find the 2.0 bits anymore of the ASP.NET AJAX Control Toolkit. Indeed, when you navigate to the Releases tab of the project on Codeplex you'll only see this list:
source code, 3033K, uploaded Aug 21 - 24104 downloads
application, 1716K, uploaded Aug 21 - 8256 downloads
application, 512K, uploaded Aug 22 - 5704 downloads
application, 238K, uploaded Aug 22 - 2555 downloads
Phew, no more 2.0 bits. It seems that Microsoft decided to cut on keeping things rolling since SP1 of .NET 3.5 came out.