Internetcalls is a long distance and VoIP service provider based out of Switzerland. It is developed by Dellmont Sarl.
Internetcalls offers a pay-as-you-go model/free service model, similar to Skype. It also offers 120 days for free - although these days are not easy to determine in advance, nor are they guaranteed. Other than that, Internetcalls offers the low per-minute international rates we've all come to expect from an international VoIP provider.