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.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Hours - Boosting productivity through live, virtual co-working.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Futuramo Time Tracker - Futuramo Time Tracker is a time tracking solutions designed for freelancers and teams.
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.