Looking for a script that has two pictures are displayed next to each other and user can click on they like best.
Hmm, don't know of a script that does that. You could probably grab a "Rate It" script (*there's a bunch of free ones... the most popular example being Hot or Not) and code one yourself from there. If you can't, I'm sure there are coders on here who would do it for a couple bucks.
I think that onicdesigns.com was selling the original, I bought a copy a while ago, and the support was great, and for the money, even greater. They even solved a problem that I had and that wasn't included in the price! I would recommend them. And it's exactly that script, photo battle script. I have no ties with them...