FluentPS is an open source library to simplify development and improve maintainability of Project Server 2010 custom solutions by providing ORM-like interface to PSI. Utilizing FluentPS, you can access your data in form of plain .NET objects. Mapping is defined with attributes.
Project is evolving, and the documentation is coming soon. You can watch the progress and find preliminary documentation in our blog at http://www.projectserver2010blog.com/
Feedback is welcome!