Voting is now open for the Round of 64. The voting hub is being hosted at Gamer Theory (bandwidth reasons), and you'll head over there for links to the individual polls. There are 4 regions, just like in the NCAA tournament. Make sure to vote in each region. You can abstain from a vote if you are unfamiliar with a game, but you're encouraged to vote for each match up regardless.
Feel free to discuss your votes and the results here. Also, you don't have to have submitted a bracket to participate in voting. Spread the word and let's get some votes rolling in!
To vote, head here: http://gamertheory.com/story.aspx/417/Pinball+March+Madness+Voting/