Ebay CEO John Donahoe, speaking at a retail conference in Barcelona, has revealed that roughly ten percent of all iPhone and iPod touch users have downloaded the Skype application. According to the Wall Street Journal, Donahoe said that within 24 hours of its launch, Skype was the top application on the IPhone in 40 countries. Ebay purchased Skype in September 2005, and plans to spin the VoIP service off as a separate company with an IPO announced…