Link directory plugins for Wordpress will create a list of the links and/or link categories you have defined in the links section of the Wordpress administration panel. These lists can be shown on pages and/or posts. On another website of mine use a link directory plugin for the list of free webdesign resources on the internet.

Here are a couple of free and commercial link directory plugins that I have evaluated in my own search of a good link directory plugin.

Free plugins

Business Directory
Plugin homepage · Wordpress Extend · Demo

Link Library (my personal favorite)
Plugin homepage · Wordpress Extend · Demo 1 | Demo 2

WordPress Link Directory
Plugin homepage · Wordpress Extend · Demo

WP-Directory Wordpress Plugin
Plugin homepage · Wordpress Extend · Demo

Web Directory Wordpress Plugin
Plugin homepage · Wordpress Extend · Demo

WP-Directory-List
Plugin homepage · Wordpress Extend · Demo not available

Commercial

CNCat Component
Plugin homepage · Demo

WPDirectory Pro
Plugin homepage · Demo