Microsoft Knowledge Base Article 272235 contains the following summary:

Windows 2000 has two Internet Connector license types that are used for different functions and are installed in different ways. For more information about the Windows 2000 Internet Connector license types, please see the following Microsoft Web site:

The Windows 2000 Server Internet Connector license is used to allow Web users to be authenticated by a Web server without having to purchase individual licenses for every user.

Windows 2000 Server Internet Connector License

This license allows for an unlimited number of authenticated Internet connections. This license type does not contain Terminal Services client access licenses.

This license type is configured through Internet Information Services. For additional information about the Windows 2000 Internet Connector license, click the following article number to view the article in the Microsoft Knowledge Base:
279031 No Method of Installation for Internet Connector Licensing Option

Windows 2000 Terminal Services Internet Connector License

Allows 200 concurrent users to connect anonymously to a Terminal Services server over the Internet. Available only in the Select Volume Software licensing program.

Windows 2000 Pricing Information

For Windows 2000 pricing information, please see the following Microsoft Web site:

Which Internet Connector License Pack to Purchase

The two Windows 2000 Internet Connector license packs each serve a different purpose. The correct pack should be chosen based on your connection requirements.

If you want clients to be able to connect to a Web site and have authenticated connections over the Internet, you need the Windows 2000 Server Internet Connector license for unlimited connections. If you need up to 200 concurrent non-employees to connect anonymously to a Windows 2000 Terminal Services server, you need the Windows 2000 Terminal Services Internet Connector license.

Windows 2000 Client Access Licensing Overview

For an overview of Windows 2000 Client Access licensing, please see the following Microsoft Web site: