Ad-hoc networks are an emerging technology with immense potential. Providing support for large-scale service and application deployment in these networks, however is crucial to make them a viable alternative. The lack of infrastructure, coupled with the time-varying characteristics of ad-hoc networks, brings about new challenges to the design and deployment of applications. This paper addresses these challenges and presents a unified, overlay-based service architecture to support large-scale service and application deployment in ad-hoc networks. We discuss the main functionalities of the architecture and describe the algorithms for object registration and discovery. Finally, the proposed architecture was evaluated using simulations and the results show that the architecture performs well under different network conditions.