Brax Cisco, Wesley Hopper, and Michael Eaton have just beta-released their wonderful “Zodiac Decrypto” program, a fun piece of software designed to attack the Zodiac ciphers as well as other substitution ciphers. It uses letter-level n-gram frequency analysis (no, not Engram analysis!) to estimate the validity of solutions generated by the software’s hillclimbing process. The software runs in Windows.
Give it a shot!