Great article on how to build documentation from Source Files
XML Comments Let You Build Documentation Directly From Your Visual Studio .NET Source Files by J. Andrew Schafer
C# allows developers to embed XML comments into their source files—a useful facility, especially when more than one programmer is working on the same code. The C# parser can expand these XML tags to provide additional information and export them to an external document for further processing. This article shows how to use XML comments and explains the relevant tags. The author demonstrates how to set up your project to export your XML comments into convenient documentation for the benefit of other developers. He also shows how to use comments to generate help files.