Continental card
The Continental phone card is one of the most versatile cards on the market.
For example, PC to phone calls to India from US are cost about 0.10c/m. (See whole table)
Preparations for call are simple.
1.    Please Sign Up before downloading a softphone.
2. Get you PC to Phone / Prepaid VoIP Account username and password - go to My Account,
select WEBCALL -> PC to Phone option next to Continental card.
3. Choose your operating system to download a softphone.

Skype
You can easy and quite cheap to call both local and international phones and mobiles directly from
Skype. There is the clever guide inside Skype how to dial the number the right way (including those
tricky plusses or double zeroes you need sometimes).
But of course first of all you need to - down load and install program to you computer. You cannot
register an account on Skype website but once you have created a Skype Name you can use it to log
in to your account to purchase products like Skype Credit (so you can call phones and mobiles). In
fact there are two options for payment for PC to phone calls:

Pay As You Go- Add money to your account and start calling. Call locally, nationally or internationally. For example, PC to phone calls to India from US are cost 0.092c/m. (See whole table )
Pay Monthly- Unlimited calls to a country or region. You may call any time of the day, any day of the
week.
You can - choose any ones .

For sure there are other ways for PC to phone calls to India but these two I described most optimal
by my opinion.