Internet Service Providers
When you connect one or more PCs to the Internet, you will need to hire the services of an "Internet Service Provider" or "ISP". Generally, these companies utilize either your local telephone line to bring "DSL" service to you, or they utilize your local cable TV connection to bring you "Cable Modem" service. Monthly prices range from about U.S. $12.00 to about $100.00, depending upon desired speed, claimed reliability, distance to the nearest ISP facility, local legislation, etc.
More information about ISPs will be available here in the future. For now, you might enjoy these movies which mention ISPs and some of their basic service options:
Ethernet Delivers Internet
The 7-Layer Vocabulary of Modern Internetworking