Developer maps for Office, SharePoint and InfoPath

You can download them via:
http://www.microsoft.com/downloads/details.aspx?FamilyId=771AEB45-9D27-4D1F-ACD1-9B950637D64E&displaylang=en.

ASP.NET AJAX

ASP.NET AJAX is a free framework for quickly creating a new generation of more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers.

Read the
ASP.NET AJAX Showcase

This is a cool site developed using ASP.NET AJAX
http://www.pageflakes.com/

Microsoft is spending lots of $$$ on catching up these Web 2.0 things. I guess more will come soon :)