Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Teamgantt - Intuitive project planning and collaboration. Beautiful Gantt charts, task-level communication, file sharing, resource management and more.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Basecamp - A simple and elegant project management system.
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.