Free 20 minutes international call
click on following link and register to get 20 free international calling minutes :

I'm posting this cuz its a freebie, but Before you go signing up I would recommend you READ the terms of Service, as it states "As soon as your call is connected to a phone number provided by Rebtel, the call may be charged by your provider, regardless of whether you are connected to a receiver of the call (e.g. even if the line is busy).

Which doesn't sound overly free to me. JMHO