The terms IAPs and ISP (Internet Service Providers) are often used interchangeably, though some people consider IAPs to be a subset of ISPs. Whereas IAPs offer only Internet access, ISPs may provide additional services, such as leased lines (T-1 or T-3) and Web development. In contrast to both IAPs and ISPs, online services provide their own proprietary content in addition to Internet access.

Russ Haynal's ISP Page
Contains resources that "every ISP employee should know about the Internet." Includes links to backbone maps, global interconnection points, Internet architecture data, etc.

Internet provider FAQ
Provides information on how to become an internet service provider. Key topics covered are: equipment, billing, competition, legal issues, marketing information, technical problems, a glossary, and links to related resources.

The List - A database of Internet Service Providers
The database at 'The List' site contains thousands of Internet Service Providers from around the world. The database is searchable by entering the ISP name or domain name, or you can choose from a variety of several categories to locate an ISP near you.