Perseus Digital Library
Great source for sources!
Perseus is an evolving digital library, engineering interactions through time, space, and language. Our primary goal is to bring a wide range of source materials to as large an audience as possible. We anticipate that greater accessibility to the sources for the study of the humanities will strengthen the quality of questions, lead to new avenues of research, and connect more people through the connection of ideas.

Philosophy Pages
Offers helpful information about philosophy including:
The Dictionary of Philosophical Terms and Names.
A survey of the History of Western Philosophy.
A Timeline for the intellectual figures discussed here.
Detailed discussion of several major Philosophers.
Summary treatment of the elementary principles of Logic
A generic Study Guide for students of philosophy.
Links to other philosophy Sites on the Internet.
An opportunity to download the entire site for personal use.

The Internet Encyclopedia of Philosophy
As the title suggests, this is a complete online Encyclopedia. A university level resource.

Welcome to the Mortimer J. Adler Archives
This site is devoted to the recently deceased champion of Great Books, Mortimer Adler. Some think he was an anti-intellectual reactionary, while others think he was a great defender of seminal works in the development of liberal democracy. You decide.

Overview
Another useful explanation of fallacies. Organized into three types: Fallacies of Relevance, Fallacies of Presumption, and Other Fallacies. Again, just click on the name and get an explanation and examples.

Fallacies
Based on the work of Dr. Michael C. Labossiere, this page covers many of the informal fallacies, from Ad Hominem to Tu Quoque (Two Wrongs Make a Right) using clear English explanations and examples. An attractive and useful site.