I don't think you can, however there are plenty of free web texting services out there.
Updated: You definitely can call from PC to Phone in India and from or to anywhere in the world. It is well known software Skype and there are several others. I found one list here at tech-diggers.com, in their search bar type free phone calls and you should see a list of 17 free calling apps which works on both mobile or pc.
how do I make a free call from my computer
Enter the number into the phone and call it.
*67
you can use calling cards to india(prepaid and postpaid). These cards are very cheap..Check this dial91 dot com for cheap pinless Calling card for making cheap calls to India.
Use skype
from reebtel.com
Aniruddha shivhare
You don't.
I don't think this is possible. You can call from a PC to another PC anywhere in the world but you can't call mobiles for free.
Moula saudi
You cannot make a free call really. You can have free nights and weekends with certain cell phone plans or make free calls to certain users, but you still have to pay for the phone and pay a minimal monthly fee. You can sometimes make free local calls with a landline but you still have to pay a monthly fee for that as well.
If the computer and the phone have Gizmo software installed, then this is possible. You can do free calls to India mobiles and landlines through ADPHONE software. Install the software on your PC, and link your Facebook account with ADPHONE account. You willget some credit points. With every 10 points, you will be able to make 3 minutes of free call to any Indian mobile or landline phone. For more information about this one please click on the link "Free Call".