Need a PHP posting system similar to craigslist

I need scripts written that will process my forms similar to craigslist. Users will have the ability to upload up to 6 photos with their ads. The scripts must provide server side validation of the form imputs. Each post must contain a unique 7 - 10 digit post id so users can update or edit their ads. If you are not familiar with craigslist's posting system, please check it out so you know what I am looking for. This is the first phase of production and their will be future need of your help and I would like to find someone that I can work with throughout this project. I would like the scripts to be heavily commented as I would like to learn in this process as well.