If you are an ASP.NET developer and have either Visual Studio 2005 or Visual Studio 2008 and want to learn how to build web applications using AJAX, then this is the site for you.  The Microsoft ASP.NET team has made available about 30 videos (ranging from 3 minutes to 30 minutes) that show to use most if not all of the ASP.NET AJAX controls.

Here's a link to the full list of videos: (Click here to view them)

Here's a sample of a few of them (see below):

#1 | How Do I:
Get Started with ASP.NET AJAX?

7 minutes, 51 seconds

#2 | How Do I:
Get Started with the ASP.NET AJAX Control Toolkit?

11 minutes, 15 seconds

#3 | How Do I:
Use the ASP.NET AJAX CascadingDropDown Control Extender?

27 minutes, 56 seconds

#4 | How Do I:
Implement Dynamic Partial-Page Updates with ASP.NET AJAX?

12 minutes, 7 seconds

#5 | How Do I:
Make Client-Side Network Callbacks with ASP.NET AJAX?

15 minutes, 26 seconds

#6 | How Do I:
Add ASP.NET AJAX Features to an Existing Web Application?

7 minutes, 20 seconds

~Robert Shelton