Microsoft has offered all the Indian users of Skype to make free calls to the mobile numbers and land lines of the United States and Canada. This is open for all the India users of all platforms (Android, iOS, Windows, Windows Phone) and should have a valid Skype account and an internet connection to make the phone call for. This offer is open until March 1, 2015.
The procedure is simple as any call you would make through Skype so far. You just need to log in into your Skype account and dial the number you want to make a call to. Make sure you have your data/internet connection on before you proceed to make any calls.