Mobile code is more and more accepted as a promising alternative for structuring distributed applications. The messenger paradigm is the approach to mobile code used in this paper. Messengers are threads of control that can move in a network of messenger platforms to search for resources and information they need to accomplish their task. They are expressed in the MØ messenger language and are interpreted by messenger platforms. MØ is one such platform. We present in this paper an architecture for distributed services in a messenger environment, i.e., for services implemented with messengers and that are designed to run in a network of messenger platforms. The interaction between a service and its consummers (for example between a server and a client) requires that the interaction interface be known by the two parties before interaction can occur. The classical approach is to establish this interface at development time, making it quite impossible for a client to interact with a service for which it has not been prepared for. With the combined potential of mobile code and code interpretation, it is no longer necessary to know the service interface at development time in order to implement a client that can interact appropriately with the service. In fact, the service is published with its operational interface which describes the necessary information to interact with it. The client discovers the service at run time time, interprets its interface description and collects from it at that moment the necessary information to interact with the service. A service interface is described in an interface description language that is understood by the service clients. Moreover, the use of mobile code and the ability to generate and interpret code on-the-fly make it useless to predefine a protocol in order to achieve interaction between a service and its client. The service can unilateraly move code on the client side where it is executed.