Microsoft has released Sandcastle - March 2007 Community Technology Preview (CTP)

Sandcastle produces accurate, MSDN style, comprehensive documentation by reflecting over the source assemblies and optionally integrating XML Documentation Comments. Sandcastle has the following key features:

Works with or without authored comments

Supports Generics and .NET Framework 2.0

Sandcastle has 2 main components (MrefBuilder and Build Assembler)

MrefBuilder generates reflection xml file for Build Assembler

Build Assembler includes syntax generation, transformation..etc

Sandcastle is used internally to build .Net Framework documentation

Sandcastle - March 2007 Community Technology Preview (CTP)