Bitphone has been released! Place international calls with your Bitcoin or Altcoin. No need to register. Anonymous calls, use a custom caller Id and more!
Check it out:
https://bitphone.netNo doubt this is an advance website but unlike what you said registrations is needed, the $5 btc bonus is reasonable but I cannot ascertain the cost per minute though it appear cheap, so OP should try to include the call rates per country, it might help.