There is no doubt that Skype is a great service, but it seems that more often than not there is something about the service that for some reason or another, does not seem to work at 100% and that is a real shame.
But there is an alternative and it is called Indoona, this is a service similar to Skype, offering messaging, video and voice calling and more importantly all for free. It uses a wireless connection or 3G, so this means it can be used on Smartphone’s and tablets too.
This how the internet phone service Indoona works;
With indoona, you can call all other indoona users anywhere in the world from your PC or your smartphone. In addition, thanks to the indoona address book, you can see at any given time which contacts are online and have the indoona application installed. In this way, calling them for free couldn’t be easier.
Source [Coolest Gadgets]