The seminar will cover two levels. The first level will be based on research in the area of ubiquitous computing, with emphasis on mobile computing. We will look for applications already developed for US markets, for African countries, and Cambodia, India, and China. We are interested in tracing the common trends and explore the differences. We use, the practical and theoretical works of Tapan Parikh (Berkley) concerning the development of applications for the Informal Economies. On the second, most important level we will develop our own applications. We are first targeting the Senegalese market. We will collaborate with two Senegalese Universities to develop, as a particular case, Mobile Phone applications for businesses connected with the WBC.