It should work the same in many other area codes too, call your local telco customer service rep to find out. Since most of these are voice-only, it is very easy to program a large number of people to start calling your mark on short notice, and the target gets stuck with the bill. Forwarding to your phone comany's local security office is a sign of true arrogance on your part, as everyone gets hosed. Do it sometime. Forward calls to a number that is not in service.
Effect is self explanatory.
Be warned that some phoneco's have gotten wind of this concept and installed anti-loop safeguards. Forward to voice-mail systems. As any phone freak worthy of his k-bud box knows, telephones require certain specific voltage levels in order to operate. Run them too far below these voltages, and they crap out and die. Run them too high, and they blow up and melt.