The OpenRate open source rating and mediation engine is the oldest of the Open BSS Alliance projects, and is therefore the most mature and stable. In daily production use at leading reference sites, it is the foundation stone that other projects (Notably OpenBRM) rely on. OpenRate comes from a background in Telecommunications, but today is in use within utilities and logistics organizations as well. OpenRate started as a community project, and still has active links with the open source community in general.
The community information (Wiki, Javadoc, Howto and installation documents) is at: OpenRate Community Site.