Facebook allowed users on Friday to make free calls to friends at the leading social network using its application tailored for iPhones or iPads. An updated Facebook "app" for the popular Apple mobile devices shows when friends are online and then gives the option of ringing them up Upgrades in the Facebook 5.5 app included a button designed to make it easier to "like" online content and post comments at the social network. Calls are routed over the Internet using telecom service data plans or connections to Wi-Fi hotspots. MUST READ: Samsung's Galaxy S4 to be launched on March 14 Two more Emirates 24|7 readers win BlackBerry Z10 Du offers prepaid and postpaid services with BlackBerry Z10 BlackBerry 10 Dubai launch: Will RIM’s first real innovation in 10 years be its last? BlackBerry 10 launch pushes Bold prices down BlackBerry is back! Availability, specs and prices of BlackBerry Z10 and Q10 unveiled