Display multiple clocks in Windows
Microsoft Windows Vista and Windows 7 can show multiple clocks at once. You can use this feature to monitor the current time in different parts of the world. For example, the example below uses multiple clocks to show the local time, Eastern Standard Time, and the time in New Delhi, India.
To add more than one clock, click the Change date and time settings... and then in the Date and Time window, as shown below click the Additional Clocks tab. In the Additional Clocks tab, check the first Show this clock box, then select the time zone for the second clock, and the name of the clock. If you want more than two clocks repeat the same steps for the third clock. Once all clocks have been enabled click OK and now when hovering over the time and date in the Taskbar or clicking on the time you should see all new time zones.