New challenging service scenarios are integrating mobile wireless devices with limited and heterogeneous capabilities. This not only calls for novel solutions to support different forms of mobility and connectivity in wired-wireless integrated networks, but also stresses the necessity of quality of service (QoS) tailoring and adaptation, especially in resource-consuming applications such as multimedia distribution. The work presents mobile ubiQoS, a mobile agent (MA) middleware to manage the QoS provisioning of multimedia content to client devices that roam in the wireless Internet. In particular, the paper focuses on how mobile ubiQoS provides a portable solution to predict inter-cell mobility, without any external global positioning system. Mobility prediction permits to migrate personalized MAs, which tailor/adapt multimedia contents to both device profiles and user preferences, by anticipating user movements. This is crucial to proactively rearrange personalized sessions by maintaining service continuity. The adopted prediction solution is lightweight and decentralized, by exploiting the client-side monitoring information about the received signal strength of IEEE 802.11 base stations in a completely portable way. Both simulation and experimental results show that, notwithstanding the portable application-level approach, our middleware can predict the. next user cell location enough in advance to support continuous multimedia services for the wireless Internet.