Mobile phone applications are becoming more and more popular. As the technology advances, services like camera, accelerator meters, compass, GPS, etc. are provided by the mobile phones. However, the more smart phones become smarter, the more the design of complex applications covering the various user needs becomes a complicated task. To support an End-User in the development of mobile applications we present a visual approach to enable End-Users to compose visually their own applications directly on their mobile phone. The methodology enables the end-user to develop applications and/or compose services on the smart phone, so making the way towards new scenarios where smart phones replace and overtake the Personal Computer, given their native possibility of wide connectivity, when augmented by features for interaction with remote systems and sensors. Moreover, the results of a preliminary usability study revealed a good satisfaction degree and the effectiveness and efficacy of the Micro App visual approach.