A major challenge faced by teachers nowadays relates to the usage of proper educational technology to achieve a true and meaningful learning experience involving time for reflection. Teachers constantly seek new ways to improve instruction, but in virtual learning environments they often find themselves in a new role, interacting in a dynamic system with students and simultaneously acquiring new skills related to the tools in use. In this paper we address this question by conducting an online course aimed at primary and secondary school mathematics teachers, designed to investigate the effective use of GeoGebra and Moodle. The tools selected for the course are free and easy to use, an important factor for the new technology to be incorporated into teaching practice. The course results show that a well-constructed proposal is able to meet the expectations of teachers. Furthermore, the usage of new technologies involves, beyond technical issues, changes in the behavior and in the relationships between the actors involved.