Time Buddy - Time Buddy brings a colorful world clock.
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Time Zones Converter - Time Zones Converter is an application which as the name implies, is used for converting time zones.
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
World Clock - World Clock is an app that lets you see the time of any city in the world.
Pomodone - Pomodone is the easiest way to track your workflow using Pomodoro technique, on top of your current task management service.