Determine your goals in starting a mentoring program. Outline the nature of the interaction between mentors and mentees, the intensity and frequency of the mentorship, and other factors related to implementation of the program.
Secure monetary and participatory support from administrators or executives. You might even consider having your organization's administrators participate directly as mentors, or in some other visible capacity.
Pair up mentors and mentees according to their profiles, career interests and goals, and the overall vision of the mentoring program. Alternatively, establish a loose framework by which mentors and mentees find each other, and then go ahead with meeting and interacting according to more rigid scheduling.
Schedule meetings and activities for mentors and mentees, at least in the beginning. This will get the ball rolling and allow relationships of trust and friendship to form. After the first few meetings, let program participants take the initiative to meet and interact as they see fit.
Keep up with the program's progress. You don't need to check in more than once a month, but it's important to evaluate how well the mentoring program's goals have been implemented. Also, get feedback from participants.