Ask LDmom from CC - her vote was already cast when she went to the polls in 2008.
After our experience with my two sons and a neice and a nephew in the 2008 presidential election, I have turned to absentee voting. I also have everyone request them early, so that if we need to priority mail their ballot to their college dorm, it can be done quickly! After my kids and my nieces had trouble in 2008 with their voter registrations/never receiving sample ballots or getting their absentees very late in the game, I realized it happens more often than it should. These kids (4 of them) all had the opportunity to vote in their first presidential election. All of them had some sort of issue that made it difficult for them to vote.
I think it's laughable that we don't ask for identification to vote. We have had this conversation before about all the places that we are asked to show identification on a routine basis. And honestly, if they don't have any identification, how do they get a job, go to school, collect government benefits,drive, etc?