In this work, we discuss various aspects of the application of pervasive technologies inside an urban setting. In the last decade we have seen the emergence of a multitude of closely-related pervasive technologies that have only recently started to materialize on a grand scale, such as wireless sensor networks, RFID and NFC. We discuss the arising research challenges associated with such converging fields and we also provide a survey of the state-of-the-art related application scenaria, which we believe set their near-future applied context. Finally, we provide a more analytic discussion on three discrete systems that belong to this category of applications and give insight to the current state-of-the-art work in this field.