forall x is an introduction to propositional logic and first order predicate logic with identity. Covers symbolisation, formal semantics and proof theory for each language. Also includes many practice exercises.
A powerful, and fairly simple program to map arguments and debates. Can interface with other users online.
A set of tutorials and exercises within logic and critical thinking. Full access requires paying, however the example videos show technical accuracy and simplicity.
An excellent site with detailed lessons on formal and informal logic and reasoning.
A website with a list of fallacies. Linked is a nice interactive taxonomy of fallacies used by the website.