These were some useful links on Microsoft Ajax preview 6
http://weblogs.asp.net/InfinitiesLoop/
http://weblogs.asp.net/jimwang/default.aspx
http://weblogs.asp.net/Bleroy/
Microsoft Ajax Preview 6 Download Page
This post by Scott Guthrie is really amazing
http://weblogs.asp.net/scottgu/archive/2009/10/15/announcing-microsoft-ajax-library-preview-6-and-the-microsoft-ajax-minifier.aspx
This preview is quite inetersting as it supports both two way databinding for clientside Datacontext and JQuery based scripts which makes JQuery deveopers life easy with Microsoft Ajax.
Thanks,
Thani