tinyPM is a web-based agile collaboration tool best suited for organizations running many projects with multiple distributed teams. Although it's already a mature solution it evolves rapidly (new versions released every 1-2 months) and still keeps its easy to use interface and structure.

tinyPM is not bound to any particular agile flavor but fits perfectly into any method that uses concepts of iterative development and user stories as the main mean to gather requirements. It supports a product development life cycle starting from raw concepts and ideas that land in a sandbox, through prioritized backlog with user stories, task board used daily by development teams and ending in the acceptance area.

tinyPM provides all the standard functionalities you may expect from an agile tool (backlog and task board with drag and drop support, burndown charts, estimations in story points, etc.), but it also add some unique features like project budget tracking or integrated 5-in-1 wiki. tinyPM has been already translated into 10 language with a great support from community users.