VoIP pioneer Skype has confirmed recent speculation by unveiling a version of its software for Apple’s App Store. The eBay-owned company said in a statement today that the client will work with both the iPhone and iTouch, and offer free on-net (Skype to Skype) calls on a global basis and reduced calling rates to other numbers. However, unlike many rival mobile VoIP services, calls made using ‘Skype for iPhone’ can only be accessed via Wi-Fi hotspots and not via standard mobile networks. The application’s IM functionality will work over 3G, Wi-Fi, GPRS or EDGE, though Skype warned that an unlimited data usage plan would be necessary to avoid high network charges. “Skype software for the iPhone has been the number one request among our users,” said Scott Durchslag, chief operating officer at Skype, which boasts over 400 million users.

Skype already offers a version of its software for Microsoft’s Windows Mobile platform and has also recently announced a version called ‘Skype Lite’ for Google’s Android platform. A version for the BlackBerry is expected in May. Other mobile developments include a tie-up announced at the GSMA Mobile World Congress last month between the VoIP firm and Nokia that will see Skype pre-installed into Nokia’s smartphones, starting with the N-Series later this year. Back in 2006, Skype also struck a deal with 3 UK for development of the 3 Skypephone that has sold around 500,000 units. However, until now, iPhone users could only access Skype via third-party applications such as Fring or Truphone. In an e-mailed statement to Mobile Business Briefing, Truphone welcomed the launch of ‘Skype for iPhone’ but claimed its own service offered a number of advantages, including the ability to make VoIP calls via mobile networks and connect to multiple IM communities (MSN, Yahoo, Google Talk etc.). Skype’s service could also run into issues with the mobile operators that carry the iPhone, some of which have banned VoIP and P2P software over their networks.