Sweden seems to be the home of VoIP apps. Skype can arguably be traced back to Sweden, Rebtel is bigger than most everyone realizes, and Plingm is tackling the huge growing markets. Plingm is probably the least known company on the list, which is probably due to the fact that the company rebranded from Freephoo last May.

Plingm’s strategy is to make it as easy as possible to get set up with Plingm, and forgoes the whole username idea, preferring to draw from the phone’s phonebook as well as LinkedIn and Facebook integration. The company also offers its calling prices in a different format – they advertise calling the the U.S. as 50 minutes for $2.99, for example.

That makes it difficult for me to compare prices next to Skype, but it may help explain their growing popularity in the Middle East and Africa, where the price point they’re competing against has traditionally been the fixed price-per-time-period idea of calling cards.

The company has also translated their app to Arabic, which they describe has helped them grow. “We are witnessing an influx of new mobile VoIP users in Middle East and Northern Africa. With Plingm in Arabic, we believe that many more will discover the benefits of free communication,” says Pandelis Eliopoulos, Plingm co-founder.

The company still faces stiff competition. In Egypt’s app store, for example, six of the top 10 free social networking apps are VoIP apps.