Various arrangements that allow you to phone over the Internet
For those who have never seen or touched VoIP, here's an introduction to the different ways in which VoIP is used:
This is the most common way to use VoIP. Its simplicity has helped make Vonage and AT&T CallVantage so big so fast. These VoIP services give you a phone adapter as part of a sign-up package. This adapter allows you to use your conventional phone (allowing you to keep your regular phone number, as many services advertise).
You simply plug your phone into the adapter instead of into the wall socket, and the adapter connects to your computer or your Internet connection.
This phone adaptor is called an analog telephone adaptor (ATA). The ATA converts analog (the traditional way information is transmitted with a continuously variable signal) to digital (the most efficient way information is now stored and transmitted - the mode primarily used across the Internet).
These look very much like regular phones and (like the ATA) these are available from your VoIP provider. They connect directly to your router via an Ethernet connector. All of the software necessary to make an IP call is found right inside the phone.
Computer-to-Computer, or Computer-to-Telephone
Some say this the easiest way to use VoIP. With this, you purchase (or download for free) software that allows you to turn your computer into a phone. Typically, you will use your keyboard or a virtual keypad to type in numbers. You will need a microphone, a sound card and broadband Internet (cable or DSL).
Skype has established itself as the biggest name in computer-to-computer VoIP, offering a basic service for free with premium upgrades that will cost money. You can use this and other computer-to-computer VoIP services to phone any landline in North America as well as anyone else connected to the service anywhere in the world. Skype also offers a great introduction to VoIP.
VoIP and Net use
All of these allow you to continue using the web to surf or even chat with other people.