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.
Any website related to the following topics is welcome:

Algorithms Automata, Complexity and Computability Logic, Semantics and Theory of Programming Natural Computing Cryptography and Security Combinatorics Distributed algorithms, Quantum Computing, Games, etc.

The study of algorithmic complexity. A topic of particular interest is the relationship between polynomial-time (P) and non-deterministic polynomial-time (NP), the latter consisting of algorithms for which there is a P solution given the right initial guess (often called witness or certificate).
The conferences of Theoretical Computer Science.
Formal language theory is defined to be the study of sets of words over finite alphabets. In formal language theory a word in a language can be accepted by a device (automaton) or generated by a grammar. The four languages of the Chomsky hierarchy (regular, context free, context sensitive and recursively enumerable languages) are typically studied.
Online Forums and Networks discussing aspects of Theoretical Computer Science.
Important journals of theoretical computer science.
The people actively involved in research in theoretical computer science.
Please submit sites dealing with simulation of quantum computers, quantum programming languages and other software related to research in quantum information theory.
Academic Research Groups in Theoretical Computer Science.
Software related to theoretical computer science.