I came across this excellent post on the problems with Sandcastle, the Microsoft offering for generating help documentation for .NET 2.0 assemblies. In addition to pointing out the problems with Sandcastle, the author (Grant Drake) brings us up to date on the status of other successors to NDoc.
As someone who used NDoc 1.3 a lot on projects in the last couple of years, I was very disappointed that the author decided to discontinue work on NDoc 2 (especially since we have mailbombers to thank for the loss).