TOP 5 software for free international calls :

1) VoipCheap : - I'm talking about the original version and not that of voipcheap. co.uk. Although both companies use the same software, I found this software more reliable and voice quality is high. It is an advantage when it comes to making long distance calls free. With VoipCheap you can call almost more than 50 countries on landlines and mobile With some hacks, you can call countries not included in the list of free countries.
Advantages:
- Call from your PC.
- No need to purchase credits
- Clear voice,
Cons: really none.

2) Jajah: The difference between JAJAH and other VoIP providers is that Jajah lets you make calls from your mobile phone or landline, simply visit the site and type your number in a box, then the one we want to call in another. Moments later, the phone rings in both places. So we do not need a helmet (using traditional handsets).
Advantages:
- No contract, no software, no helmet,
- Easy to use
- No credit needed for free calls.
Disadvantages: you can not use a PC to make a call

3) Gizmo 5: Also known as the Gizmo Project. This software allows you to call anyone in more than 60 countries. The only drawback is that you and other parties must be registered with Gizmo and should also save your numbers.
Advantages:
- Calling is easier than ever
- Super clear call quality
Disadvantages:
Requires that both parties must register their numbers Gizmo.

4)Mobivox: One of the top VoIP providers that I prefer, like JAJAH, you do not need to install software on your mobile or even on your PC. A registration service you give 10 minutes of free calls to over 60 countries. And one other strong point of this software is to enable you to make calls to Skype contacts from your mobile phone for free.
Advantages:
- Improved technology
- Very clear call quality,
- 10 free minutes, no software
Cons: None.

5) Pfingo: This is a new service that will give you a free phone number to make and receive calls via a small software "Pfingo talk" that you can download to your pc. At registration they give you like $ 3 credit test after you have to buy credit.