XBAP (XAML Browser Application) is a new Windows technology used for creating Rich Internet Applications.

While windows applications are normally compiled to an .exe file, browser applications are compiled to an extension .xbap and can be run inside Internet Explorer.

Xbap applications are run within a security sandbox to prevent untrusted applications from controlling local system resources. (e.g  deleting local files)

What is XBap.org

This is a site for everything related to XBAP. It includes articles, press release, tutorials, webpages, discussion, blogs, tools, and other many other resources.

For a start there is a FAQ here for beginners

FAQ

The following is a tutorial to help you create your first XBAP application

Tutorial

Pit yourself against artificial intelligence in the Tic Tac Toe sample below.

Samples