BK-Works ProPHP
ProPHP is a simple ad-swap network that you can install on your own webserver. Once installed, users will be able to register their websites and upload ads to your website. The program will auto-generate javascripts based on the user's ID, and the user will never have their own ads show up on their website.
Webserver Requirements
It is suggested that you have at least PHP 4 or 5 (tested more thoroughly on 5).
File uploads must be turned on.
MySQL 4
Potential Problems
Please note that I have not put any work into this project since early 2007.
There is currently an SQL exploit that would allow an unauthorized user to log in, but not to any particular user's account.
License
This project is released under the GPL License Version 3. Any future versions may be released under a different license.