Wrike - Wrike is a flexible, scalable, and easy-to-use collaborative work management software that helps high-performance teams organize and accomplish their work. Try it now.
Taiga - Project management platform for agile developers & designers
Leantime - Lean project management for startups & small teams
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.
Producteev - Producteev is a free task management application for individuals and teams to collaborate via the web, email, IM, mobile or desktop.
TargetProcess - Agile Project Management Web Application