One million downloads for the Skype application for iPhones has helped the software become one of the fastest-downloaded apps ever, it has been reported.
The application has achieved its impressive take-up within just six days, meaning that six people have downloaded it every second.
iPhone owners can use the application to make free Skype-to-Skype calls using a wireless broadband connection.
They also benefit from significantly cheaper calls to landlines.
News of the success of the Skype app is set to stir up controversy between mobile phone manufacturers and networks who regard Skype as a huge threat to their business model.
Scott McElry, vice president of operations at AT&T, told Unstrung: "With Skype and VoIP clients in general, we don't prohibit them on our network, but at the same time we don't encourage them on our network.”
In response to these concerns, earlier this year Orange and O2 declined to carry Nokia’s Skype-enabled flagship handset the Nokia N97 on their networks.