Recently we started a small project and decided to try Basecamp, a collaboration tools from 37signals, authors of the famous Ruby on Rails framework.
Basecamp is a unique project collaboration tool. Projects don't fail from a lack of charts, graphs, or reports, they fail from a lack of communication and collaboration. Basecamp makes it simple to communicate and collaborate on projects.
Give this web application a try, it is really smart: it allows you to be productive in few minutes and incredibly facilitates teams collaboration. Each single operation is clean , simple and intuitive, making a wise use of Ajax widgets. We are testing the free edition, which comes with some limitations but it is good enough to start. Then it is possible to upgrade to a professional edition if you realize you need more horse-power. However, pricing looks very competitive.