Last year I wrote an article on how to view multiple time zones in the Outlook 2007 Calendar.  We can do a similar trick to view multiple time zones on the Vista Desktop as well.  This comes in very handy if you are doing business internationally, or in different time zones within the United States.

First right click on the time display in the lower right hand corner of the Taskbar and select Adjust Date / Time.

This will open up the Date and Time dialog box.  Select the 'Additional Clocks' tab and place a checkmark next to each clock you want to display.  Your local time will always show, so you can add two additional clocks in different time zones.  Select the appropriate time zone and enter a familiar display name for each.

After the appropriate time zones have been set up, when you click on the time display you will get the following display of each time zone you set up.

Also, if you just hover over the time display on the Taskbar you will get a smaller pop up display.  To further enhance this display you can follow The Geek's tip on enabling Military Time as well.