It requires no registration, and unconditional free unlimited VoIP calls to mobiles and landlines. Here’s how you can setup your GTalk2VoIP account Open GTalk and press the Add button to add a contact.

1. click on the Add button to add a friend,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: phonenumber@talkster.gtalk2voip.com Example: for UK, use 442071234567@talkster.gtalk2voip.com or for USA , use 12125551212@talkster.gtalk2voip.com
2. You’ll get a confirmation from Talkster with instructions and an SMS sent to your friend with his local Talkster call-in number if you called a mobile number and your friend is added to the list, and you can make calls any time.

For more details on how to call, check out the official site here. Here’s the press release on the launch of GTalk2VoIP GTalk2VoIP – HomePage