Google Voice is a great service to make cheap international calls and even if your iPhone came with unlimited free incoming calls and data plans, you can save a lot by using Google Voice with iPhone. With an unlimited data plans you can not only make free local free calls you can also make very cheap international calls.
First of all you need a Google Voice account. There are two catches here. The first is that it’s invite-only, that is, you need to be invited to have a Google Voice account (simply having an iPhone won’t do). The second catch is that Google Voice is available only in the USA.
Anyway, assuming that you are in the USA and you own an iPhone and you don’t have a Google Voice account you can get an account by heading to this link: https://services.google.com/fb/forms/googlevoiceinvite/
Once you’re lucky to have an account log into your Google Voice account and select the Phones tab under settings. There, make Google Voice forward all the calls to your iPhone.
Then you can manually add the names and the phone numbers to your Google Voice account or you can import them from friendly and compatible sources. After having done that, through your iPhone log onto http://voice.google.com/m/ and go to the contacts section where you have added all your contacts.
That’s it. Once you click on one of your contacts Google Voice first calls your iPhone and then connects the call to your contact and you can have a long chat without burning a whole into your pocket.
If you buy some credit from Google Voice you can also make cheap international calls from your iPhone.