The work carried out in the thesis describes efficient virtual environments management. One of the main contributions is a middleware scheduling optimization based on Grid environments. Being the overall goal to get an optimal resource selection plus a coordinate task execution optimization. In particular, the research was related with the interaction between non trivial quality service and tasks distribution issues in meta-organizations. While linking allocation and policies belonging to virtual and local organizations.Es revisión de: http://sedici.unlp.edu.ar/handle/10915/4175Resumen de tesis presentada por el autor para obtener el título de Doctor en Ciencias Informáticas (UNLP, 2010).Facultad de Informática