Jacqie just posted another great intro article about writing an app with db4o and ASP.NET MVC. It's a VisualStudio solution with a very simple model but it includes tests and a web app (ASP.NET MVC3). The project relies on db4o v8 for .NET 4.0 providing a Db4oSession that derives from ISession. Additionally it provides a SessionFactory that handles the database connections.

The blog post is available here (source code included!)