Mentoring refers to the phenomenon where a more skilled or knowledgeable person helps a less skilled or less knowledgeable person gain skill in a particular domain. In this paper we study the phenomenon of mentoring in a massive multiplayer online role-playing game (MMORPG). We identify four different types of mentoring, which map to several important motivational features. We then measure the social networks of mentors at multiple levels, and propose a network model to describe the emergence and evolution of mentoring. Keywords; Mentoring, Social Networks, MMORGP, Mentoring Networks