Rick,

More information would be helpful. As other posters have mentioned: How are you serving the Ad links up?? That will give us a better idea of what needs to be done...

I'll make some assumptions. To me, every ad you display probably looks like this:

   <a href="adtracker.cgi?uid=12345&aid=123929&redirect=1">
      <img src="someimage.gif" alt="Buy this car!"/>
   </a>
[download]

When someone clicks the ad, they are first sent to a 'front controller' for your ad server (adtracker.cgi) This controller is a mod_perl/cgi script that inspects the params, writes the stats to a DB/logfile, and forwards off the advertisers site. You might need to write this.

No matter how you slice it, really, somewhere along the way you need to capture the ad click. That ad click has to be a GET/POST to your webserver.

Give us more details, and we'll tell you other ways to abuse URLs to get what you need. ;-)

Kurt