I just released the embeddable NHibernate console for web applications I wrote some months ago. You can get the binary here, it also includes a sample application so you can play with it and see how it's configured. The only requirements for NHWebConsole are .NET 3.5 and NHibernate 2.1.2.
It hasn't changed much since I first wrote about it. I fixed a couple of bugs and added HQL Intellisense thanks to Fatica Labs' wonderful HQL Editor. It's not overly pretty but it mostly works. Here's a screenshot:
Source code and documentation is on github.
Let me know if you use it and/or if you find any bugs!