How to run a photography contest using WordPress?

I would like to host a photography contest from my WordPress blog and allow users to either upload photos into certain categories (or I could post them for them) and basically allow visitors to come and vote on one from each category with only one vote per category allowed per IP address. I wouldn’t want these photos to run in my main loop but could be accessed from another page.

Any ideas on how to pull this off? or is there another recommend tool to do something like this.