The integration of Web Services and Software Agents brings new opportunities and helps in defining new kinds of services too. A very interesting approach comes from the adoption of "Mobile Agents" to design and develop a Service Oriented Architecture that supports the access to distributed services by heterogeneous handheld devices. This paper describes the functional model and the architecture design of a platform for services composition and delivery. Mobile agents are able to access and compose services accessing them by standard interfaces. User authentication, service discovery and publication, personalization are other provided facilities. Technological interoperability is provided by Web Services technology. Code mobility is exploited to reconfigure the server platform moving agents to the available nodes, or to reconfigure the user devices providing it with the needed client software.