Microsoft Time Zone works with Windows XP and Windows server 2003 and required .NET frame works 1.1 installed on your PC. After downloading and installing the utility, run the program. It will sits in the system tray and allows you to easily view the date and time in various locations with a single mouse click. Right click on the Microsoft Time Zone tray icon to add new time zones. (via)
Microsoft Time Zone lets you know the time and date in multiple locations in the world simultaneously (only five locations at a time). This may be useful for those who works with people from other countries or for those who want to keep abreast of time in various places in the world. You can add your own personal locations from the option menu to customize Microsoft Time Zone the way you want.