I always find it a good idea to take information straight from the horse's mouth - i.e. use the tutorial at the
NHibernate[
^] site and then refer to the various How-to articles on the same link.
Just because the article you found is out of date does not necessarily mean it is of no use to you ... the fundamentals haven't changed that much. I notice that people are still giving the article good reviews and 5-starts even up to October of this year (it's often a good guide to look at the dates of comments on articles, you can also get an idea if the author is still active on the site by their responses)