Mission: Critical
Tutorial for critical thinking.
http://www.sjsu.edu/depts/itl/index.html

An Experiment in Group Learning Technology
The results of a study designed to measure critical thinking in face-to-face and computer-supported seminars.
http://www.qub.ac.uk/mgt/papers/ccvsem/contents.html

The Critical Thinking Community
Providing a forum and resources about Socratic questioning, higher order thinking, and critical thinking. Organizer of conferences and publisher of books and academic resources for teachers.
http://www.criticalthinking.org/

Real-World Reasoning
A course given by Peter Suber for high-school students as an introduction to college.
http://www.earlham.edu/~peters/courses/inflogic/inflhome.htm

So You Want to Avoid Common Logical Errors?
Gives logical errors a name and points out the most common logical errors and how to avoid them.
http://www.soyouwanna.com/site/syws/logic/logic.html

Are You Being Brainwashed and Manipulated?
Discussion of mass manipulation techniques and how to resist them.
http://members.aol.com/opsgreen/

Association for Informal Logic and Critical Thinking (AILACT)
A non-profit scholarly association which aims to promote research into, teaching of, and testing of informal logic and critical thinking.
http://ailact.mcmaster.ca/

Free Thought
One person's introduction to critical thinking, logic, belief, and free thought.
http://freethought.homestead.com/

The Church of Critical Thinking
Dedicated to spreading the word about cynical reasoning in established religion, politics, the paranormal beliefs, as well as anything else that people tend to accept blindly. "Your Suspicion is Our Mission".
http://www.churchofcriticalthinking.com/

Philadelphia Association for Critical Thinking
Addressing strange phenomena with the mindset, "What are the facts and what can we deduce from them?"
http://www.phact.org/

Thinking Straight: Internet Resources
Categorized directory of web-based resources on critical thinking.
http://www.limbicnutrition.com/critical/

2think.org
Collection of book reviews and essays, mostly on popular science, with an emphasis on science as a guide to truth. Also includes a discussion forum.
http://www.2think.org/

A Field Guide to Critical Thinking (Skeptical Inquirer Winter 1990)
Six rules of evidential reasoning, a distillation and simplification of the scientific method. Ignoring the vowels, the letters in the word "FiLCHeRS" stand for the rules of Falsifiability, Logic, Comprehensiveness, Honesty, Replicability, and Sufficiency.
http://www.csicop.org/si/9012/critical-thinking.html

National Center for Teaching Thinking
A service organization for educators dedicated to providing programs for K - 12 schools and colleges on teaching and assessing skillful thinking,.
http://www.nctt.net

Propaganda and How to Recognize It
Essay on propaganda techniques.
http://www.rbs0.com/propaganda.pdf

Open Courseware on Critical Thinking
Over one hundred tutorials on critical thinking, logic, scientific reasoning, creativity, and other aspects of thinking skills.
http://philosophy.hku.hk/think/

Critical Thinking across the Curriculum Project
Definitions, examples and argument analysis, from Longview Community College.
http://mcckc.edu/longview/ctac/

Critical Thinking Study Topics
Student study guide on psychological manipulation, cult groups, sects, and new religious movements.
http://www.icsahome.com/infoserv_topic_collections/tpcol_critical_thinking.asp

Resources for Independent Thinking
Many essays and articles covering topics related to thinking for one's self.
http://www.rit.org/essays/essays.html

The Business of Thinking
On applied thinking, the pitfalls and roadblocks to good thinking, and effective techniques.
http://www.thebusinessofthinking.biz

Skeptopix
A collection of links to audio and video files, all on skeptical topics. Lectures, interviews, discussions.
http://home.scarlet.be/~tsg15649/

Responsible Thinking
Online book by Bob Korn promoting critical thinking. Outline, contact information.
http://www.truthpizza.org/

Skeptical Analysis of the Paranormal Society (SAPS)
A group devoted to debunking, re-creating, and explaining popular claims of paranormal activity.
http://skepticalanalysis.com/

Digital Bits Skeptic
Skepticism and critical thinking articles.
http://www.dbskeptic.com/