This paper discusses knowledge sharing in the corporate environment. It studies different barriers for knowledge sharing as well as incentive programs that are aiming to motivate employees to engage in the knowledge sharing activity. Finally it presents a new Peer-to-Peer (P2P) knowledge sharing paradigm and the architecture of a mobile peer-to-peer knowledge sharing system. The proposed P2P knowledge sharing paradigm addresses the major issues of mobile communication as well as human aspects of social interactions. It supports communities and utilizes strengths of peer-to-peer social networks. The system implementation proves technical feasibility of the proposed approach.