This information applies to Windows Internet Explorer 7 and Windows Internet Explorer 8.
You can use your computer to send and receive phone calls over the Internet, even with people who are not set up for Internet calling. Windows Vista does not include the ability to send or receive phone calls over the Internet, but is compatible with the calling equipment and software used by most Internet calling services.
The sheer variety of Internet calling services has exploded in recent years, as placing calls over the Internet changed from a rare practice attempted only by technically savvy computer users into a mass-market service used by millions of ordinary people. In general, however, there are just two basic kinds of Internet calling services: those that require you to place calls from a computer, and those that don't require a computer. Internet phone services that do not require a computer enable you to place calls from a handset connected to your router, often via an adapter box that plugs into the router. Services that require a computer to make calls enable you to control all your calls and voice-mail messages through software installed on your computer, while you talk through a headset or handset attached to your computer. All require you to have an always-on, broadband Internet connection.
Regardless of what Internet calling equipment you choose, you'll need to sign up with an Internet calling service provider. Before selecting an Internet calling service, find out what software and calling equipment they require. Many service providers will sell you everything you need, including phones or headsets and some type of phone adapter or base station that plugs into your router or computer. Ask your service provider about compatibility before buying any Internet calling equipment. Equipment from one service provider may not work with another calling service.
Internet calling is referred to by many different names, including VoIP (Voice over Internet Protocol), IP telephony, Internet telephony, broadband telephony, broadband phone, and voice over broadband.