AutoSim
A free automata simulator that simulates DFA/NFA/DPDA/NPDA/STM
AutoSim is a free automata simulator for students and educators. Written in Java, it is a command-line based utility that runs on any OS that supports Java. With AutoSim, you can not only determine the final state or stack/tape contents, you can also trace through the execution states as well, from the initial to the final states. The latest version of AutoSim is 1.0, and it currently supports DFAs, NFAs, DPDAs, NPDAs, as well as Standard Turing Machines.