Speaking as someone who owned one of the most popular adult image vote sites out there,
http://www.RateNudePeople.com , I'd say DON'T USE I-RATER! Instead, go with
http://www.superchargedsoftware.com/index.php?sc=39 . They have a free demo that you can setup and install on your own site. It's super duper sweet, though! If you want to see it in action, go to the link above!