Useful Links related to Theory of Computation

Tutorials on Discrete Math

http://www.otal.umd.edu/drweb/induction/tutorial.html
http://www.cc.gatech.edu/people/home/idris/AlgorithmsProject/ProofMethods/
http://mathforum.org/library/drmath/view/54256.html
http://mathforum.org/library/drmath/view/54204.html

Sites on Finite State Automata and Regular Expressions

http://www.xrce.xerox.com/competencies/content-analysis/fst/home.en.html
http://www.cs.sunysb.edu/~algorith/implement/grail/implement.shtml
http://grid.let.rug.nl/~vannoord/papers/fsa/fsa.html
http://www.cs.ukc.ac.uk/pubs/2000/958/
http://www.lib.uchicago.edu/keith/tcl-course/topics/regexp.html
http://www.jflap.org/
http://www.robotwisdom.com/net/regexres.html

C++ Template Classes for Regular Expressions, NFAs and DFAs.

http://www3.sympatico.ca/dbiggar/FA.home.html

Visual and Interactive Tools From Duke University
Many tools, mostly in Java, to explore finite automata and context-free languages.

http://www.cs.duke.edu/~rodger/tools/tools.html

Turing Machines

A Turing Machine Simulator in Java: http://www.cs.binghamton.edu/~lander/tm_source/tmdoc.html
Universal Turing Machine (with code in Scheme)
A Site about Alan Turing
A TM simulator in Scheme

Sites on Complexity and NP- Completeness

NP Optimization Problems http://www.nada.kth.se/~viggo/problemlist/compendium.html
http://www.nist.gov/dads/
http://www.uncg.edu/mat/avg/avgnp/survey.html