Internet Telephony (Voice over Internet Protocol - VoIP) is the technology used for making telephone calls over the Internet. Using an internet telephony service means that you can make cheap calls anywhere through a fast Internet connection.
To get started you will need either a piece of internet telephony hardware such as an IP Phone, a VoIP adapter, a VoIP router or a softphone. All of the products that can be used are available to buy online and a suitable softphone can be downloaded from www.xten.com.