Banner / Ad Management Script

Hello, I am looking for a great Banner / Ad Management Script for my website. I have mulitple locations on my site where I want to allow my users to advertise. Users should be able to use the Banner/Ad Management Script to view locations available, choose a location, upload ad/banner, submit payment, etc. This script should be able to run seperate from my website, but just require that I copy and paste some code into each of the ad locations. Code will allow all ads/banners for that location to be displayed. This is a very simple project/script. Thanks, BCBC