BYTE -- Here's how to add and display clocks for multiple time zones in Vista and Windows 7.
First, click on the clock on the Task Bar in the lower left corner on the Taskbar. Click on Change Date and Time Settings.
Now select the Additional Clocks tab, check Show this Clock, then choose the time zone you need.
If you want an additional clock, follow the same steps as you did for the first one. If you want the clocks to be displayed, check Show this clock.
In the Enter display name field, enter the city or country and click OK.
Now when you click on the Clock in on the Task Bar, you will see the clocks you added and what time it is in those locations.
If you want a quick look at what time it is in different parts of the world, just hover your mouse over the clock and it will show.
Follow the exact same steps in Vista gets you the same effect.
If you're a Windows user and work with people from around the world, seeing what time it is in their location is very helpful!