Since March of 2008, the“nhusers” google group mailing list has been going strong full of discussion by NHibernate users. Merely searching the archives provides a wealth of information on solutions to various challenges. If you have an NHibernate question, come visit the list and ask it. Also, hang around. You might be able to help someone else out who is just getting started with NHibernate.
Anecdotally, I started using NHibernate version 0.8 on .Net 1.1, so I’ve seen it grow and mature over the years. It is a terrific Object-Relational Mapper. If you want some more structured information, go get the NHibernate in Action book.