In this paper we present the results of research work, that forms part of the activities of the EU-funded project SLOOP: Sharing Learning Objects in an Open Perspective, aimed at encouraging the definition, development and management of Open Educational Resources based on the Learning Object paradigm (Wiley, 2000). We present a model of Open Learning Object (OpenLO) for a greater awareness in the use of LOs by teachers, giving them a more active role in the evolution of educational resources; the OpenLO model extends the concept of reusability, providing pedagogical sustainability. Moreover, we compare FreeLOms, a Learning Object Management System that implements the proposed OpenLO model, to traditional tools for handling LOs.