PHP Link Directory
The PHP Link Directory script aims to offer a complete Link Directory solution. The directory only requires certain software that is common to most web hosting packages, and provides the following features:
Manage multiple level category tree - sub categories can go as deep as you want;
Makes use of mod_rewrite (if you wish) in order to make every category and link appear as a seperate static page - great for search engine optimization and human readability of links;
Easy to customize - easy to change global settings with detailed help every step of the way (you don't need to be a programmer to run this directory!);
Automatic validation of reciprocal links - if your server supports it, the reciprocal link can be checked before a submission is even accepted;
Easy to install - just a couple of minutes till you're up and running!