So one of the things I guess every brewer does is figure out how much alcohol is in your beer.
Looking online, I found this formula at 'How Stuff Works',
which is basically (Original Gravity - Final Gravity) * 1.05/Original Gravity.
In my case, I screwed up and forgot to write down my original gravity. I think it was 1.062, and I had a final gravity of 1.010. Applying the formula, that works out to:
(1.062 - 1.010) * 1.05 / 1.062 = .052 * 1.05 / 1.062
In other words, 5.14% alc. in my beer.