VoIP (also know as Voice over IP), stands for "Voice over Internet Protocol", or in layman's terms simply the process of holding a telephone conversation over your Internet connection.

VoIP is more taxing on your network than streaming audio as it requires realtime, two-way transmission with sufficient bandwidth for audio coming in and going out at the same time without being able to buffer any of it.

Therefore the speed of your computer and it's health, any internal networking and the quality of your Broadband and it's bandwidth become even more important.

Most Internet Providers offer there own VoIP platform, however at present one of the most well know providers of VoIP are Skype.  As well as Skype, most other IM's (Instant Messagers), such as Microsoft's Windows Live Messenger, have the facility to use VoIP and also Video Calls.

Since VoIP requires a great deal of steady bandwidth to be able to cope with multiple incoming and outgoing calls, it is mainly used for middle to large companies to help reduce their cost in telephony.  However there are still many home users of MSN and Skype.

Many communications companies, such as Tiscali , who offer broadband to home users are fully aware of the implications of free calls using VoIP.  Therefore these companies have introduced many broadband bundles which include free landline telephone calls to local, national and international numbers.  Since these free call options are manly for home users, business are the current driving force for VoIP.