phpExchange allows you to run your own banner exchange. Each member in the Exchange can distribute his own banner ads across the Exchange, and the ads are displayed based on a system of credits. phpExchange keeps track of all impressions and click-through stats for each clients and your clients can view the stats for their advertisement online.

phpBannerExchange is a fully functional banner exchange application. Features include multiple banners per account, raw mode (for admin only at this time), account statistics for individual accounts, Admin approval of accounts, ability to remove banners/edit accounts from admin control panel, Automatic email notification of new accounts to admin (and ability to turn them off), and much more. Built by banner exchange admins FOR banner exchange...

Banex is a nice PHP/MySQL banner exchange program with anti-cheat functions, admin panel, ratios and more. Version 2 includes huge improvements to the administration panel and layout, and also adds multi-banners per user support. Mods available.