The Project Leader is a person who “leads” a team, and must take care and administrate the lower level of technical details of the Project (definitions, etc.). A Project Leader focuses on the internal side of the Project and ensures that the team is working efficiently and effectively to finish the Project on time, and must also validate that the finished product meets customer requirements.
The Project Leader is more technical and has the responsibility of fulfilling the Project using the resources that the team has in a correct way.