CO-ODE(site info)
Collaborative Open Ontology Development Environment is a project led by the Medical Informatics Group at the University of Manchester.
http://www.co-ode.org/
On-To-Knowledge(site info)
A project of the European Information Society Technologies, under 5th Framework Program (1999-2002). The project develops knowledge management methods and tools, based on ontology sharing and reuse.
http://www.ontoknowledge.org/
5.
Buffalo Ontology Site(site info)
Large collection of links and papers about Contemporary Ontology, History of Ontology and Ontological Engineering. From the Department of Philosophy, State University of New York.
http://ontology.buffalo.edu/