http://www.microsoft.com/web/downloads/webapptoolkits/

“These FREE Web App Toolkits help you complete common web development tasks and quickly add new features to your apps. Whether it’s Bing Maps integration or adding social capabilities to your site, there’s a toolkit for you. Download and install them today.”

http://blogs.msdn.com/webapptoolkits/

My friend and coworker Vlad made me aware of these.  I’ve been living in the dark.  Apparently, they have been around since September.  I didn’t even know they exist until last week. 

Here’s a dump of all the toolkits available as of today:

Web App Toolkit for "Freemium" Applications
Web App Toolkit for Calendars
Web App Toolkit for Bing Maps
Web App Toolkit for IE8
Web App Toolkit for Bing Search
Web App Toolkit for REST Services
Web App Toolkit for Mobile Web Applications
Web App Toolkit for Template-Driven Email
Web App Toolkit for Making Your Website Social
Web App Toolkit for FAQs

You will find screencasts for most of the toolkits at http://channel9.msdn.com/tags/web+application+toolkit/.  I just checked out the IE8 toolkit screencast.  You basically get ASP.NET controls that simplify the building of Web Slices, Accelerators, and Visual Search Providers for IE8.  You also get a sample site that incorporates the controls. 

I will be watching the rest of the screencasts over the next week or so.  Good Stuff!