Now most of the service providers support calling to Skype and GTalk.This is an example : <a href="http://www.dialog.lk/personal/mobile/features-and-vas/skype-services/skype-call-from-dialog-idd/I">http://www.dialog.lk/personal/mobile/features-and-vas/skype-services/skype-call-from-dialog-idd/I</a> do not see anything complex here other than bridging a Skype call with a conventional call.