The Washington Post has this handy chart to tell you if you need identification to vote, and what kind you might need: (click to enlarge)
Given all the press coverage the issue has received, I was somewhat surprised to see that the number of states where identification is a voting requirement is relatively small, although the jurisdictions where you can be asked for it but not prevented from voting is larger. What constitutes proper identification does vary from state to state, though, so one should check with the appropriate local office to ensure you have the right identification before going to the polls.
