Use PC-Telephone to make unlimited FREE PC-to-PC calls over Internet. Enter in the Phonebar the IP address or name of your contact party’s PC and press the Dial button while you are online. Your IP address is your Internet phone number. Find your IP address in the IP address combo box (Network-IP options) after establishing the Internet connection.

Skype… Just google it for it… But it is free for pc to pc.

Skype is amazing! i use it

Voip discount is cheaper and better than Skype.

One can make free pc to pc calls freely after downloading n installing Skype to any part of the world, it’s available for free download along with the google pack http://pack.google.com/intl/en/pack_installer.html?ciNum=13&hl=en
If you need to call landline or cell ph’s in US it will cost you upto 1/4th of the regular ISD ph call which makes it worthwhile. To use it you just need to sign in to create an account and charge it with a credit card.

Here is the list of the free international calls to usa

http://free-call.info
Regard