Tabrio offers free calls anywhere in world including India, Pakistan, Russia. Tabrio is in Beta phase and is offering new users Free credit worth 5$ that can be used for making calls and sending sms. Free 5$ credit will provide 35 minutes calling to India. Signup here.
Otherwise, there calling rates are high. They charge like 15 cents from US to India. Also, to avail free credit multiple times, you need to register with different phone number.
I have updated the Free calling to India – Best Signup Offers Many hours post with all the recent posts.