If you're referring to Mr CGI Guy's script I've also been playing around with it for a while @
http://www.planetofporn.net/. It does the job (and it's inexpensive), but I find it a little fiddly to customize, but then I'm not the brightest coder around.
Plus: Built-in cat specific banner management system.
BIG minus: As far as I can see the script doesn't allow for category hardlink trades.