Recently, I was searching for some good tools for generating MSDN style documentation from C# code comments. Here are few tools I came across.
Sand Castle - Provided by Microsoft, with out much official support. But serves the purpose. May take some time to configure :) - See http://blogs.msdn.com/sandcastle/
NDoc For .NET 2.0 - I don't think it is an official release of NDoc, but this one can generate code comments for VS 2005 - See http://jonas.lagerblad.com/blog/?p=5 . When you try to open a VS 2005 solution, it may say Invalid Solution, but I got around this problem by simply dragging the dll file to the 'Select Assemblies To Document' listbox before building them.