VOIP calls are carried by the normal Internet.Once you reach a point close to where your family lives (same city if posible) you need to go trought a gateway,to make the conversion from VOIP to normal PSTN. You “bypass” the long distance carrier and only pay for the local call inside the city.
The bad news:You need to find a company that will do for you, and normally they do not deal with end users. They want to have few thousand minutes a month as minimun.
Alternatives:If you have broadband and your family have or could get broadband, you buy a couple of I.P. phones and talk forever for the price of the internet conection.
If you could not get broadband, but have access to dial-up internet, get a couple of Aplio phones. For about $100.00 you will be able to talk to your familie almost for free.