Yahoo! Messenger lets you make PC-to-phone calls to and from countries around the world. The normal international call rates using the Yahoo! Voice Phone Out service to India are 7.9¢/min. But as part of Diwali celebrations in India, they are offering cheap call rates at 4.9¢/min!
You need to sign up for Phone Out, install Yahoo! Messenger and simply start calling to India! Here is the Yahoo! Voice Diwali Offer page which lets you call at 4.9¢/min from Nov 08 10:30am PST (Nov 09 12:00am IST) till Nov 09 10:29am PST (Nov 10 11:59pm IST). After Diwali deal is over, the call rate will be the usual 7.9¢/min with no connection fees. Of course you can call your friends for free with PC-to-PC Calling in Yahoo! Messenger.
Wish your friends in India a Happy Diwali today. Its easy and cheap too.