What is an Internet Service Provider?

Quite simply, a company that provides you with a connection to the Internet. They may also bundle a bunch of other services in with the deal, but basically, all you really need is the connection...the rest is just fluff.

Types of service include:
    Dial-up service - where you dial a phone number through your modem
    Digital Subscriber Line - DSL-works on your phone line, but no dialing and it's a lot faster
    Cable - through your cable television company, using their cable lines
    Direct-connect - the fastest connection, uses terms like T1, T3, etc.