Answer:
A truth table evaluator is a computer program that evaluates a truth table, i.e., it produces the truth value of a statement for all possible values of its variables.
There are at least a few on the web:
Brian Borowski's TT Constructor (http://www.brian-borowski.com/index.html)
Joole (http://stephan-brumme.com/programming/Joole/)
Orion Transfer TT Evaluator (http://svn.oriontransfer.org/TruthTable/)
Lawrence Turner's TT Evaluator (http://turner.faculty.swau.edu/mathematics/materialslibrary/truth/)