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.

Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.

Hours - Boosting productivity through live, virtual co-working.

Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.

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

Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.