The last five years has seen a shift in the nature of mobile computers. The development of increasingly powerful laptop computer systems has been mirrored by the production of a range of small computational devices. The increased prominence of these devices outlined a number of distinct research challenges. These challenges have tended to focus on extending the utility of these devices using new forms of interaction; techniques to overcome display limitations or improvements in the general ergonomics of these devices. The merging of these devices with existing telecommunication services and the production of devices that offer connections to other systems presents yet another set of research challenges in terms of the development of cooperative multi-user applications.