Dmoz
The Open Directory Project is the largest, most comprehensive human-edited directory of the Web. It is constructed and maintained by a vast, global community of volunteer editors.

Alpha-Bids
Alpha-Bids is a directory script with a built in bidding system. Not only does it organize listing alphabetically but it allows users to improve the Alpha-Bids rank by paying for a bid.
Business Listing Directory
Frontend Users: Browse through categories / ads Register to post ads Purchase Standard Ad to Higher Priced Ads - Free Ad Placement too Upload upto 4 images per listing Add Website Revise images and listings at anytime Renew your account Forget your...
PHP Directory Software
PHP Directory Software (PHP Directory Script) is a top quality PHP script for launching your own Search Engine Friendly (SEO) Link Directory web site. It has a great potential to generate very heavy revenues for you. It is built with a focus on search engine visibility , increased ease of users...