Additional
Information: Theoretical Computer Science is the mathematical foundation of computing in all its forms. By being the foundation, it is also the starting point for new and more efficient methodologies of computation.
Computability Logic Computability Logic: Main web source on the subject: overview, downloadable articles, links. (Theoretical) http://www.cis.upenn.edu/~giorgi/cl.html
Church-Turing Thesis Church-Turing Thesis: Wikipedia article. (Theoretical) http://en.wikipedia.org/wiki/Church-Turing_thesis
Computability Theory Computability Theory: Wikipedia article. (Theoretical) http://en.wikipedia.org/wiki/Computability_theory
Theoretical Computer Science on the Web Theoretical Computer Science on the Web: A directory of resources related to theoretical computer science from Stanford University. (Theoretical) http://robotics.stanford.edu/~suresh/theory/theory-home.html
Interactive Computation Interactive Computation: Wikipedia article. (Theoretical) http://en.wikipedia.org/wiki/Interactive_computation
Theory of Computation Theory of Computation: Lecture notes for an undergraduate class taught by Leonid Levin at UC Berkeley. (Theoretical) http://www.cs.bu.edu/fac/lnd/toc/
An Introduction to the Theory of Computation An Introduction to the Theory of Computation: An online text aimed at advanced undergraduate and graduate students. (Theoretical) http://www.cis.ohio-state.edu/~gurari/theory-bk/theory-bk.html