Ubiquitous Computing (Ubicomp) is a term first coined by Mark Weiser [1] more than a decade ago. In his vision, computers are no longer isolated objects sitting on the desk, but surround us everywhere: walls could be electronic boards and displays; books could be electronic information stores and cameras act as digital picture libraries. Some of this vision has already come true with wall-sized Smart Boards that support writing, editing and capturing of electronic text, while PDAs can be used for diaries, e-books and note-taking, where some of them are also integrated with digital cameras. While such computers largely follow the PC paradigm, where one computer is dedicated to one user at one point in time, new types of computer systems are arising in Ubicomp that are invisibly embedded into our everyday environment.