Mobile devices are, at present, dramatically unhomogeneous for visualization and audio reproduction characteristics. Consequently, today multimedia delivery systems are very customized for some device profile or for wireless connection type. Transcoding techniques are used in order to adapt the same media source to the multiple hardware profiles. Client-based transcoding techniques show their weakness in energy consumption, and server-based transcoding techniques suffer from scalability problems. In this paper we propose a scalable distributed multimedia server based on the grid computing paradigm, which can adapt media content to the device profile and/or to the connection link.