In open mobile environments, mobile device may be connected to several network system offering heterogeneous sets of services using different names. The services can be anything and introduced by anybody, which results to have the possibility of having similar service with different names or different services having the same name. The current IEEE 802.21 Media Independent Handover Services facilitate handover across these heterogeneous networks. However, the standard just provides network continuity without ensuring service continuity during the handover. We propose extensions to the MIH, which enable the exchange of service information in addition to network information at handover. This service information constitutes the fundament for a novel service discovery capable of discovering equivalent services and enabling the handover between them. In this paper, the extended MIH handover procedure is explained thoroughly. The proposed service discovery system developed on Android is presented and a few use scenarios are given for illustration.