The home environment becomes ready to host distributed devices dynamically adapting to service availability and reacting to user location and user activity. Sensors, high definition rendering systems, home gateways, wired and wireless controllable equipments are now available. Many protocols enable connectivity and interaction between devices. However, challenges remain: protocol heterogeneity, interface fragmentation and device composition static aspect make self-organization and dynamic reconfiguration hardly achievable. This paper describes attractive scenarios at home which lead to the definition of the pervasive service composition requirements. A software architecture facing the mentioned challenges is proposed over OSGi. It first enables developers to implement distributed plug-n-play applications like a local one. It also delivers a serviceoriented middleware allowing spontaneous distributed service composition to occur at runtime.