It's a secret ballot by 5 judges announced at Dragon*Con-- the winner is secret even from the judges.
I also want to point out that this is THE Geek Podcast award. There are the ENnies, but they don't know anything about podcasts so it's not too big of a deal. There are other podcast awards, but they focus on the more typical podcasts. This is like the Oscars of Geek Podcasting.
And... I just bought a plane ticket! I'm committed! I decided if I didn't just buy a ticket I would find an excuse to chicken out. I leave at 6 am on Saturday morning (blahh!!!) but it means I'll be there for all day Sat and Sunday and even some of Monday.