The partially connected nature of mobile and ubiquitous computing environments presents software developers with hard challenges. Mobile code has been suggested as a natural fit for simplifying software development for these environments. However, existing strategies for discovering mobile code assume an underlying fixed, stable network. An alternative approach is required for mobile environments, where network size may be unknown and reliability cannot be guaranteed. This paper introduces AMOS, a mobile object platform augmented with a structured overlay network that provides a fully decentralised approach to the discovery of mobile objects. We demonstrate how this technique has better reliability and scalability properties than existing strategies, with minimal communication overhead. Building upon this novel discovery strategy, we show how load balancing of mobile objects in an AMOS network can be achieved through probabilistic means.