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.
Taiga - Project management platform for agile developers & designers
Redmine - Flexible project management web application
Plan.io - Planio makes web based project management and team collaboration more efficient and fun. It is the perfect platform for your projects, team members and clients.
Basecamp - A simple and elegant project management system.
TargetProcess - Agile Project Management Web Application