TClock Light is a very handy applications that allows you to modify the clock on the taskbar in Windows.

Highly recommended!

Free download here

1. download
2. unzip to a directory (e.g., C:\Program files\TClockLight\)
3. create a shortcut to tclock.exe in your START | All Programs | *Startup* folder
4. reboot
5. right-click on your taskbar clock and select "TClock Properties", then "Clock | Format"
6. Configure to your liking.