Php-simple-banner-rotation is a project mainly written in ..., it's free.
A simple banner rotator that will change position of banners.
I wrote a very simple banner rotater that can rotate all images in a directory hourly or daily.
Put your banners in the $dir
Set the filename to this format:
images/banners/website.com.gif
Where you include the website's address as the filename.
See the index.php for usage and example.