- We present a task modeling infrastructure for smart phone applications. The infrastructure consists of a generic task model (TM) and software tool-TM Designer-which allow a modeler to create task models that support tracking smart phone users and analyzing their use of smart phone applications. The syntax of the TM include smart phones applications, goals of applications, screens included in each application, and the possible transitions from any goal or screen to another goals and screens. In addition, the TM includes physical representations of the TM components for aligning and matching the logic TM with the physical smart phone while tracking the phone usage. Since the TM aims at modeling various smart phone applications for different mobile devices, a specific inheritance mechanism was developed to enable the reuse of TM components. Based on the tracked usage data, the service provider will be able to learn about the efficiency of the smart phone usage, predict the intentions of the users while operating the device, and provide appropriate help. In addition, the gathered usage information will enable discovering patterns of use of various applications, and predict users' interests in existing and new smart phone services and applications.