Service Oriented architecture (SOA) on Mobile Ad hoc NETwork (MANET) promotes the effort to deploy the day to day business and other services over the ad hoc mobile environments. In this paper several research challenges have been summarized related to the service publishing, registration indexing, availability, discovery and composition on dynamic environment of MANET. Several general issues related to SOA which may affect the functionality of MANET, also have been raised. Moreover, various security issues related to service deployment in MANET have been discussed. The research issues have been categorized based on the related underlying architectures of MANET like, centralized, distributed and peerto-peer (P2P).