To use the Sipgate VoIP service you need only an adaptor - one end plugs into your router and the other connects to your home phone.
Calls will then be routed by Sipgate over the internet rather than your usual telco.
Sipgate software can be downloaded to your PC if you'd prefer to make calls using a headset and microphone. This makes the service ideal for conducting webcam-based video chats.
Features include voicemail and the ability to send text messages. It's free to call other Sipgate users and, because it uses the SIP, you can also use Sipgate to call users of other SIP-supported VoIP services, such as Vonage.
To make calls you'll need to credit your account, as you would with a pay-as-you-go mobile phone. Landline calls cost 1.2p per min; calls to mobiles cost 9p per min. International calls are from 1.5p for landlines and mobile phones.
Alternatively, a £5.90-per-month subscription offers 1,000 mins to UK landlines for free. Sipgate will also let you make emergency calls to 999, provided the service is activated in your account.