Jason Haley points to a really nice introduction to using NHibernate with ASP.NET, called NHibernate Best Practices with ASP.NET and Generics.
It is not the NHibernate-related topics that interested me the most about the article, but the author's inclusion of a number of development best practices for use with NHibernate and ASP.NET:
The author goes on to reference one book that I really enjoyed reading in the past, called Agile Software Development Principles, Patterns, and Practices by Robert Martin, that goes over a number of good object-oriented principles.
I haven't downloaded the source code yet to the NHibernate and ASP.NET article, but my guess is that it will be a solid example of using NHibernate with ASP.NET.
Additional Resources: