Go read Josh Marshall's post on Talking Points Memo about voter disenfranchisment, voter fraud, etc... He makes the point that perhaps we should forget all about voter registration and simply do what we do in countries where we take over after a short war, declare democracy, and then encourage every one to vote. After voting, the folks in these new bastions of democracy dip their fingers in ink so that everyone knows who has already voted.
If it is good enough for new democracies, shouldn't it be could enough for one with a little age to it? But then again, it is probably too simple of a solution. Imagine the possibilities.