Clocks - A minimal world clock app for your Mac's menubar
ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.
Clocker - Keep track of people in different time zones
LClock - Longhorn systray clock program
Spacetime - Work hour and time zone management for distributed teams.
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.