There are a number of different tools out there that will allow you to have and run a web directory. These web based applications are generally built in PHP and are basic to start with and you can extend them to your liking, but the majority of the features are already built in.

Here are some options with web directories:

iDev Web Directory 3.0

• directory only
• No article/page management
• Payments via PayPal out of the box, others are custom
• Neat and simple directory
• $49 to buy no on going fees

Website:  iDev Web Directory 3.0