Dead Logicians Society: Warwick university's very own logic society aiming to increase and stimulate interest in logic and philosophy of logic at the university. Offers news and events.
Frege's Theorem: Article in the Stanford Encylcopaedia of Philosophy, entitled `Frege's Logic, Theorem, and Foundations for Arithmetic'. Discusses the 1980 discovery of Crispin Wright that Frege's work of the Grundgesetze can be carried out in second-order logic with Hume's principle.
Humboldt State University: Argumentation and Critical Thinking Tutorial: Jay VerLinden's resource offering reviews and tests on important concepts in formal logic.
Logic: An online textbook by Garth Kemerling, explaining the basic elements of elementary logic at an undergraduate level.
Logic and Mathematics: Essay on the nature of logic and its relationship to the philosophy of mathematics, written by Stephen G. Simpson.
Nordic Journal of Philosophical Logic (NJPL): Edited at Dep. of Philosophy, Univ. of Oslo, published by Scandinavian U.P. in hard copy and on WWW. Full-text Web edition free for personal use.
Peirce's Logic: Article in the Stanford Encyclopaedia of Philosophy, by Eric Hammer.
PHILOG: The Danish Network for Philosophical Logic and its Applications.
Symbolic Logic: Online resources provided to supplement undergraduate course taught by Peter Suber. Good collection of handouts.
The Logic Course: An interactive course in formal logic, with tutorials and quizzes on critical thinking, truth-tables, and sentential.
The Troublesome Paradox: Online version of book seeking publication by Per Lundgren. Author attempts to argue that a consequence of Goedel's incompleteness theorem is that we should overturn our current approach to scientific method.
Tips on Translating English into First-Order Logic: An introductory guide by Peter Suber.
Why Aristotelian Logic does not Work: An essay at Abelard.org outlining an argument against Aristotelian syllogistic.