Some time ago I wrote an article (in Dutch) about Sandcastle and some of the available third-party tools. About one month ago, it was published in the Dutch .Net magazine. Kind of proud now it's in print. I didn't post about it before, because the article wasn't available on the internet yet. It is now and the PDF of the article can be found here:
All other articles, and older publications of the magazine can be found here:
It's in Dutch I'm afraid.