We have been using sandcastle for a few weeks now, primarily to work around some of the issues that nDoc had with generating documentation for .net 2.0 classes with generics.

Scott Hanselman has an excellent post on the release; Sandcastle - Microsoft CTP of a Help CHM file generator on the tails of the death of NDoc.

As Scott mentions in his post, don’t expect a polished product with Sandcastle, it has a long way to go, especially in regards to, ironically, documentation. Soctt’s post is also a must read for his take on the death of nDoc, and the lack of contributions to the project, despite it’s almost universal use.