In recent years, two innovative computing and communication technologies have emerged: wearable computers and wireless personal area networks. Wearable computers advance an innovative form of personal computing based on continuously worn, intelligent assistants that augment memory, intellect, communication, and physical senses. Wireless personal area networks (WPAN) are a new class of wireless networks that provide seamless ad hoc communication over short-range radio links. The convergence of these technologies creates new opportunities for technological support of social interactions and face-to-face communities. While past research has provided a partial understanding of the social potentials of wearable computers and wireless personal area networks, we know little about the software engineering aspects of such systems. This dissertation aims to remedy this situation by exploring software infrastructure and architectural support for co-present communities. In particular, the goal of this dissertation is to develop a generic wearable software platform that (1) enables spontaneous interactions in face-to-face settings, (2) aids developers in the implementation of ad hoc collaborative applications and (3) supports building of co-present communities. The contribution of this dissertation is a methodology and software platform for building wearable communities; that is, co-present communities that emerge when enough people use their wearable computers to form webs of personal relationships. Wearable communities are based upon embodied real-world human encounters augmented by wearable computers. The proposed methodology defines a conceptual framework for software support of wearable communities, and specifies a design language and development process. The software platform addresses the information needs of applications and provides developers with high-level programming abstractions. To address the utility and practicality of the methodology and software platform, the design and implementation of a number of wearable community applications are presented and experiences of using the methodology in software engineering education are reported.