There is an interest thing that you can enable Multi-Location and Time Zone Support in Vista. If you are used to crossing time-zone, this function may be quite useful. Don't worry. You don't need to install any apps or softwares.
*Open up the Date and Time Control Panel applet
*Turn to “Additional Clocks” tab
*Now you can setup two more clocks of different time-zone
*Done

www.vista123.net, easily tweak and customize your Windows Vista.
