The popularity of consuming multimedia content on mobile phones is increasing more and more, not only because of the availability of the technical infrastructure, but also because of the mobility in modern society. We are developing a mobile multimedia streaming application. The crucial factor for such applications in order to be adopted and successful is user acceptance. This paper presents the preliminary concept and design of a contextual mobile multimedia content usability study. The study is conducted within are search project on agile software development methodologies with special emphasis on Extreme Programming and continuous usability evaluation. Past work included satisfaction of the needs of end users by means of focusing on user-experience in all steps of the development process. To gain scientific relevant data, the careful design of a study is considered most important. The study which will be conducted in October 2008 will give insights into mobile HCI concerning the coherence of content types, consumption times, and consumption contexts.