1.
EpistemeLinks.com
Drawing from several sources, this page offers a searchable index of
philosophers; brief descriptions of types of philosophy; links to "Topics,
Traditions, Time Periods"; bibliographies; e-texts; journals.
2. The Internet Encyclopedia of Philosophy
This encyclopedia of people, places and ideas relating to the study of philosophy is both browsable and searchable.
3. Philosophy in Cyberspace
This is an excellent guide to philosophy resources on the Internet, with good organization and annotations. It covers "more than 1500 philosophy-related sites, over 300 mailing lists and approximately 60 newsgroups." Major sections are Philosophy Topics, Text-Related Resources, Organizations, Discussion Forums, and Miscellaneous.
4. The Philosophy Research Base
"The Philosophy Research Base, categorized by history, subject and author, features thousands of annotated links and text resources for philosophy research on the Internet."
5. Stanford Encyclopedia of Philosophy
An online, dynamic searchable encyclopedia of philosophical concepts.