Philosophy Resources

General

Stanford Encyclopedia of Philosophy
Stanford's web encyclopedia project. A work already useful and still growing.
PhilPapers
A "comprehensive directory of online philosophical articles and books by academic philosophers." A great research tool. Oh, check out their survey of what professional philosophers think about this and that.
The UD Library's Philosophy Resources
Especially recommended are Philosopher's Index (powerful search of philosophical publications) and JSTOR (full-text journal articles).
EpistemeLinks
A big collection of internet philosophy resrouces.
Wise Old Sayings Philosophy Resources
A very nice range of resources, many (such as the short glossary) aimed at giving newcomers a head start.
Philosophy Experiments
Just for fun.

Logic & Critical Thinking

Critical Thinking Web
Joe Lau's informal logic and critical thinking resources at Hong Kong University (also available in Chinese). Includes a free Miniguide to Critical Thinking. But watch out - I spotted one mistake on my initial perusal - you must engage your critical brain even when you are being told about critical thinking.
Introduction to Logic
Oxford University's self-guided tutorials and exercises which introduces some formal tricks.
Thou shalt not commit logical fallacies
Well, thou probably shalt. At least there is a site that will help you put a name to what you just did.
List of Fallacies
An extensive list of formal and informal mistakes of reasoning. Dip in from time to time to build your defenses against such errors. There's also a link to a list of common misconceptions; providing at least another half hour of top quality procrastination.