I have spent a great deal of time over the last year and a half on a couple of projects architecting solutions using NHibernate and Fluent NHibernate as the preferred ORM (object relational mapper). It has really matured into a great set of products with the release of NHibernate 2.1 (especially with System.Transaction support) and Fluent NHibernate 1.0. I have also used LINQ to NHibernate 1.0 and like how that works as well, but it could be tweaked some more.
I have decided to turn that experience into training classes offered through my independent consulting company. Please check out my Training page on my company web site if you are interested.