Vista Horizons

You can add up to 2 more clocks on your Windows Vista task tray. Simply right click on the clock at the bottom right of your screen and then click Adjust Date/Time. Then click the middle tab that says Additional Clocks'. Then you can choose the time zones you like and make any label you want.

The beauty of this is that no screen-hogging side bar is needed. Simply hovering your mouse over the clock with pop up the other 2 with their labels as:

If, instead of hovering, you left click the clock you'll get a set of analog clocks and the calendar as: