Electronic discovery of the clinical trials being performed at a specific research center is a challenging task, which presently requires manual review of the center's locally maintained databases or web pages of protocol listings. Near real-time automated discovery of available trials would increase the efficiency and effectiveness of clinical trial searching, and would facilitate the development of new services for information providers and consumers. Automated discovery efforts to date have been hindered by issues such as disparate database schemas, vocabularies, and insufficient standards for easy intersystem exchange of high-level data, but adequate infrastructure now exists that make possible the development of applications for near real-time automated discovery of trials. This paper describes the current state (design and implementation) of the Web Services Specification for Publication and Discovery of Clinical Trials as developed by the Technology Task Force of the Association of American Cancer Institutes. The paper then briefly discusses a prototype web service-based application that implements the specification. Directions for evolution of this specification are also discussed.