The Open Physics Abstraction Layer (OPAL) is a library Tyler Streeter, Alan Fischer, and I have been working on for a few months. The goal of the project is to make it easy for people to start using physics simulation in their applications by providing a simple interface over the top of existing physics engines (ODE only for now, but it could be extended to use others in the future).
It's mainly helpful for people getting started with physics that don't want/need to tweak tons of parameters. It also includes a set of high-level constructs (various sensors and motors) for things like robotics simulation and a way to load complex objects and systems from an XML file. Visit the website (http://opal.sf.net) more details including the full feature list, tutorials, and API documentation.
These are screenshots from one of the sample apps, using the Ogre rendering engine (http://www.ogre3d.org).