Classical Logic
Introduction to classical logic, including completeness and Löwenheim-Skolem theorems; by Stewart Shapiro.
plato.stanford.edu Details

Computability Logic Homepage
Main online source on computability logic - a recently emerged formal theory of computational tasks and resources. Maintained by G.Japaridze.
www.cis.upenn.edu Details

Introduction to Mathematical Logic
Hyper-textbook for students by V. Detlovs and K. Podnieks.
www.ltn.lv Details

Logic
Wikipedia article.
en.wikipedia.org Details

Logic
Open Encyclopedia entry. Hierarchically organized by subareas.
open-site.org Details

Math Front: LO Logic
Front end for the logic section of the mathematics e-print arXiv.
front.math.ucdavis.edu Details

Mathematical Logic and Foundations
From The Mathematical Atlas, a resource of mathematics maintained by David Rusin. Extensive resources related to logic and set theory.
www.math.niu.edu Details

Mathematical Logic around the World
A rich collection of links to logic-related websites.
www.uni-bonn.de Details

Mind Versus Goedel by Damjan Bojadziev
Compares the mind to advanced computers and artificial intelligence, as Goedel would possibly view them.
nl.ijs.si Details