Mobility offers new possibilities for interaction and communication in education. Pervasive nature of mobile devices makes learning on the move and across time a reality. Their characteristics fit into the blended use of technology in education since they posses socializing powers, re-conceptualize learning by making it more informal, ambient, collaborative and personal. Nevertheless, the problem of creation and coordination of a learning environment based on mobile devices still exists. This article presents a system called MILE and its extensible context-aware architecture to support the use of mobile devices in blended learning environments. In the end, some experience and lessons learned during the development of the system are described.