Mathematical Logic and Foundations 
From The Mathematical Atlas, a resource of mathematics maintained by David Rusin. Extensive resources related to logic and set theory.
http://www.math.niu.edu/~rusin/known-math/index/03-XX.htmlMind Versus Goedel by Damjan Bojadziev
Compares the mind to advanced computers and artificial intelligence, as Goedel would possibly view them.
http://nl.ijs.si/~damjan/g-m-c.html
Classical Logic
Introduction to classical logic, including completeness and Löwenheim-Skolem theorems; by Stewart Shapiro.
http://plato.stanford.edu/entries/logic-classical/
Mathematical Logic around the World
A rich collection of links to logic-related websites.
http://www.uni-bonn.de/logic/world.html
Introduction to Mathematical Logic
Hyper-textbook for students by V. Detlovs and K. Podnieks.
http://www.ltn.lv/~podnieks/mlog/ml.htm
Computability Logic Homepage
Main online source on computability logic - a recently emerged formal theory of computational tasks and resources. Maintained by G.Japaridze.
http://www.cis.upenn.edu/~giorgi/cl.html
