Are you a US resident? Make free phone to phone domestic calls instantly through VoIP. Call to any US number free of cost of 10 minutes duration. Provide both the numbers and hit call – no signup required to use the service.
Here is a cool PC to phone voip based free calling service serving more than 40 countries. A worth try service which does not require a credit card to sign up. Make free calls to mobile and landlines to various countries. Make free calls upto 36 minutes per day.