You don't have to break off the ground pin from your plugs - DUH! 
Who said anything about breaking the ground pin from my plugs?
Or deal with this 'illegal modifications that require permits' BS that only applies to a few states.
15VAC is nothing, btw.
15 VAC means the metal body of the outlet is not well-grounded. That in turn means that I can't just use a 3-prong adaptor because the face-plate screw is not a good ground in my case. If it was a good ground, then it would measure ~120 VAC between the hot and the faceplate screw, rather than ~15 VAC.
What would I do?
Buy a two prong outlet if you simply need to replace an old outlet - they do still sell them. Otherwise, run the wire, install the box, and get a REAL electrician to terminate at the LP. If you use 14ga wire, terminate on a 15A breaker - if you use 12 wire, terminate on a 20A breaker. Don't use 16 wire - I have no clue why the home despot type places even sell it anymore.
A real electrician is going to connect the black hot wire to the 20 amp breaker, and the white neutral and green or bare ground to the single common bus bar, right?
An electrician is not needed for something so simple.
BTW, I didn't start this thread because I needed to know the correct way of wiring a 3-prong outlet. I already know how to do that. You wire it exactly the same as the existing 2-prong outlet with respect to the hot and neutral wires, and then the ground wire terminates at the common bus bar in the breaker box, and on the ground screw on the outlet.
I started this thread because it would be less tedious (running new wire behind the walls, through the floors, along the basement ceiling, etc., = tedious—the actual electrical termination is the easy part) to jump a short wire from the ground screw on the outlet to the neutral screw on the outlet. The reason I considered and asked about this option is because it is the
electrical equivalent of doing it the standard way.
Now, some people have pointed out reasons why it wouldn't be a good idea, due to the physical differences between the two wiring methods, and that's fine—I agree, and plan to do it the standard, approved, correct, whatever-you-want-to-call-it, way. I said as much in reply #19.