WebMatrix is a specialised, entry level AspDotNet that is available free of charge.
It includes its own IDE and uses code-in-line, instead of code-behind mechanisms found in proper AspDotNet.
Now in version 1.1 (matching the required DotNetFramework upgrade), and comes with several sample applications.
Download at http://www.asp.net/webmatrix/download.aspx?tabindex=4