We may all be connected, but until international time zones are hard wired into every one’s head; coordinating international phone calls will always be difficult. The timing has to be just right as does the format of the number you are calling. It could be something that only challenges me, but I suspect that others may have problems as well.
A good solution is http://www.timeanddate.com/worldclock/meeting.html which I heard about from the China Law Blog (http://www.chinalawblog.com/)
You simply enter the locations of the people you need to talk to, and you see a color-coded table indicating work and daylight hours for the various people.