You could use my addin, Atomineer Pro Documentation to quickly generate documentation comments in Documentation-XML, Doxygen, Qt or JavaDoc format. Then use Sandcastle (DocXml) or Doxygen (DocXml, Doxygen, Qt, Javadoc) to convert this documentation into external documentation files.
I'd recommend uing DocXml format because all the above tools work with it, and Visual Studio recognises it (it syntax colours it, and it builds the docs into its intellisense database so it appears in tool-tip help as you type class/method names into your code).
