Project-based learning is a technique that has already proved its worth, mainly in traditional classroom learning situations. We feel that it is also interesting to use it in a distance learning context, particularly to encourage collective learning. It does, however, need to be set up carefully in order to be well adapted to this learning situation. This paper suggests organizing a project-based learning activity where participants work in teams, each team being made up of learners at a distance involved in the same project. A teacher, also at a distance, then assumes the role of project leader to monitor and help the learners. Giving the project a schedule is equally important, and we recommend structuring it in stages which are themselves composed of synchronous and asynchronous phases to give the project rhythm. To support this project-based learning in a distance context, we designed and developed a computer environment that comprises all the tools necessary for the collective activities (asynchronous and synchronous communication tools, an application-sharing tool, a scheduling tool and a tool to write reports). Finally, we describe an experiment using this environment with 13/14 years old schoolchildren in the field of educational robotics.