Right now, free internet phone calls mostly require using a computer with a broadband connection. However, there are a few web services that that allow pc2phone or even phone2phone calls if one or both parties are members. Jajah and Gizmo Project are a couple of examples.

But a number of companies are trying to make sure that you don't need a computer to make VoIP calls without a computer. For example, US Robotics are introducing VoIP router devices that support Skype and other softphones without the use of a computer. A broadband Internet connection is still required. This is different from Skype Wi-Fi phones which still require that there's a computer somewhere nearby.

Sources: Computeract!ve.