tracking clicked links

I have a small local directory site for a town in the Florida keys and I would like to track the links leading to the sites listed in my small directory to see who getting what out of their listing. I know how many visitors are coming to my site but who's benefitting I haven't a clue. My server supports PHP and MYSQL

Just wrap each of your outbound links in a PHP script. So instead of <a href="http://www.somewhere.com">Text</a> you'd have <a href="http://www.myserver.com/outbound.php?url=http://www.somewhere.com">Text</a>. Your outbound.php reads the url parameter, logs it to a file or a database, and does a redirect to the URL using the header() function.

Thanks, I really appreciate the help.
mike