EpistemeLinks.com
Offers an extensive and impressive set of links to many sites related to philosophy and ethics, conveniently arranged. Click on topics, then click on ethical theory for a good idea of the sources available.
Errataic Impact
This site has a well-organized search capability, lots of material on topics in all areas of philosophy, and excellent brief biographies of many philosophers.
Peter Suber's Guide to Philosophy on the Internet
Though no new material is being added, this site has a good search engine as well as extensive links to information on specific philosophers and topics in philosophy and ethics.
The Stanford Encyclopedia of Philosophy
A wonderful online philosophy encyclopedia, excellent articles on a wide range of topics, easily searched; see the article on Social Contract Theory
Ethics Updates
For searching material in ethics, this is the place to start. Run by Lawrence M. Hinman, Professor of Philosophy at the University of San Diego, this is a very comprehensive and easily navigated site, with excellent links. Also offers a wide range of very good case studies, a nice collection of video lectures on ethics, links to audio resources, and a great variety of papers on ethics (including a number of classic sources that are available online at the site). It's a treasure, especially for topics in applied ethics.
Paul's Justice Page
A good site for social contract theory, organized by Professor Paul Leighton, a criminologist and sociologist at Eastern Michigan University.
Policy Library
A good resource for information on John Rawls
Serendip
If you would like to try the prisoner's dilemma with a computer opponent, check out this site.
Serge Helfrich's Page
An excellent site that discusses the prisoner's dilemma in a number of different contexts, and also contains a nice collection of links to other sites.
