Semantic correction. You can continue to vote at your previous polling place even after you move, but you can't vote at another place until you re-register. I had moved from one part of Atlanta to another part, and as long as I was willing to carry my ass to the other side of the city - I could continue to vote at my previous polling location.
Doesn't it also lapse if you don't vote in the presidential election or something. I'm probably remembering wrong.