Would you like to know the time of the city where your relatives are living or the time of the city where you’re planing to go in vacation?
If your answer is yes, then you should set up a time zone in your Windows 7 and Vista. To do so, simply right-click on the clock in the System tray and choose Adjust Date/Time.
Next, click on Additional Clocks tab and start setting up your time zones.
After you are done, just click OK. Now when you click over the time shown in the System tray bar you will see different time zones that you have set (unfortunately you can set only two time zones)