It's one world, but keeping track of the time on the other side of the planet requires a little help and a better timepiece than the Windows system clock. One of the best is Sharp World Clock, as clean and accurate a handle as the international timekeepers it displays. You can easily set it to display any number of configurable digital or analog clocks at once in a row or grid; change their sizes, colors, backgrounds, and other aspects; and display national flags for quick visual identification. You can also show day or night indicators, sunrise and sunset times, lunar phases, time zones, and more. It also boasts a zoom-capable world map depicting day and night areas, a configurable alarm clock, a calendar with a reminder feature, and the ability to add your own audio files for alarm sounds.
Both the clocks the program creates and its efficient, intuitive interface are unusually attractive and competently configured without being cluttered or garish, making subtle but effective use of color for highlighting and emphasis, even in the command dialogs. The clocks themselves, and the analog clock faces in particular, have high visual impact and readability, even at distance or a glance, but without resorting to flashy, distracting designs. In fact, they make good use of Vista-style highlighting to achieve the look of real instruments instead of a virtual display.
Sharp World Clock is free to try for 15 days and costs $39. It works in all versions of Windows from XP to 7.