My favorite story of such "one letter off" scams was between 2 major phone companies. I forget which was which now, but lets say it was AT&T that was hawking 1-800-OPERATOR as their collect call service. but if you dialed 1-800-OPERATER you got MCI (or was it sprint, I don't remember the details)
/ubbthreads/images/graemlins/grin.gif