Vonage has came up with a new app for Facebook users to make free calls anywhere in the world. The service is available for iPhone, iPod touch and Android devices.

The Vonage app is available for free download. Just install the app in your device and there is a one-time sign-in session to your Facebook. The app will have to be provided full access to your Facebook. But this is a one-time process.  Below are some screenshots that I took from iPhone.

Whenever you open the app it will show a screen like the one below suggesting you to invite some of your friends.

The service is very easy-to-use. But you do need to have your Facebook friends also install the app. Then you can make free national or international phone calls to any of those Facebook friends.

Calls can be connected over wi-fi or 3G/4G. Wi-Fi service even saves your cell phone minutes on local calls. The incoming and outgoing calls look exactly the same as usual phone calls.

 Outgoing call

Friends who are online can also be invited for a Facebook chat.

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