ERCIM, the European Research Consortium for Informatics and Mathematics, aims to foster collaborative work within the European research community and to increase co-operation with European industry. In the ERCIM eMobility workshop, current progress and future developments in the area of eMobility should be discussed and the existing gap between theory and application closed. This volume contains all accepted papers of the third eMobility workshop, which has been held in Twente, The Netherlands, on May 27 and 28, 2009. Papers from different areas have been selected for this workshop. The contributions discuss several topics of the ERCIM eMobility working group including, performance optimization in wireless and cellular networks, real world applications and case studies of WSNs and WLANs, service improvements in wireless (mesh) and fixed networks, and security and V2V communication in mobile networks. At this point, we want to thank all authors of the submitted papers and the members of the international program committee for their contribution to the success of the event and the high quality program. The proceedings are divided into two sections, full papers and short papers / extended abstracts. While the latter present work in progress and ongoing research, the full papers have been carefully selected in a peer review process. The reviewers evaluated these papers and sent the authors the comments on their work. The invited talk held by Fernando Boavida on “Ubiquitous Content Networking - The CONTENT NoE Approach” opened the NoE special session. The speaker provided some answers to the question about wether in a world full of content providers, where users can easily have Access to all kinds of content, there are still any challenges in ubiquitous content networking. The other invited talk of the NoE special session held by Aiko Pras about “Emanics - Managing the future Internet” presented Emanics, a FP6 Network of Excellence (NoE) focussing on management of future Internet infrastructures and services. The speaker pointed out the three main topics of this NoE: 1) integrating research groups within Europe, 2) disseminating knowledge to the rest of the world and 3) performing research. For the Vehicle-to-X Communications special session, the invited talk held by Thomas Michael Bohnert on “Vehicle-to-Business: Use Cases, Requirements, Architecture and Technology” presented the concept of Vehicle-to-Business. It re-visited existing business models and discussed novel models from a largescale enterprise software and platform provider's point of view. Insights in what regards the requirements on a communication platform were provided and a communication and service delivery platform was presented. The other invited talk of the Vehicle-to-X Communications special session held by Geert Heijenk about “Connect & Drive: On the use of Cooperative Adaptive Cruise Control to increase Traffic Stability and Efficiency” presented a research project carried out by a Dutch consortium of universities and industry. The project aims at designing and evaluating a cooperative adaptive cruise control system, with the goal of increasing traffic efficiency and safety, and decreasing vehicle emission. The University of Twente is an entrepreneurial research university. It was founded in 1961 and offers education and research in areas ranging from public policy studies and applied physics to biomedical technology. The UT is the Netherlands' only campus university. The next ERCIM eMobility workshop is scheduled for 2010. We hope that a lot of our participants and many new colleagues will take this opportunity to continue exchanging their knowledge and experiences devoted to the development and use of eMobility.