FREE International Calls to Any Phone from Google Talk using Talkster

Google Talk users can now make FREE international phone calls through GTalk2VoIp. The partnership between Talkster and GTalk2VoIp allows callers from any country in the world to leverage Google Talk to make free calls to or from anywhere else in the world.This service is especially beneficial to areas with strictly regulated VoIP and telecom practices, such as India and United Arab Emirates, using Talkster through GTalk2VoIP will let people communicate freely between mobile phones, landlines and PCs, even in countries not currently supported through Talkster’s ad supported free calling service.
To start, launch Google Talk on your desktop
1. Add contacts the same way you usually do: click on the Add button to add a friend
2. Type in the phone number of the person you want to call in the following format.
Use full phone number, including country code and area code (Example: for UK, use 442071234567@talkster.gtalk2voip.com)
3. You’ll get a confirmation from Talkster with instructions. Talkster assigns a local Talkster number for your friend in their country. Your friends will use Talkster phone numbers to call-in to be connected with you.
4. If you are calling your friend on a mobile phone, he will receive an SMS with his Talkster call-in number for you. Otherwise, let him know the Talkster number by IM or email. (Source)
>>More details here