Pomodone - Pomodone is the easiest way to track your workflow using Pomodoro technique, on top of your current task management service.

Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.

Futuramo Time Tracker - Futuramo Time Tracker is a time tracking solutions designed for freelancers and teams.

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.

Everhour - Everhour is one of the best time tracking tools for teams. See who’s tracking time, who’s overworked and who can handle more. Keep track of all your project budgets, schedule threshold alerts, use forward resource planning.

RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.