I'm a predoctoral research fellow at TCOM, I think that I can answer some of your questions:
Most DO schools have OMM predoctoral fellowship programs of some sort or another. The benefits and duties vary considerably at each college. At TCOM, we have both predoctoral RESEARCH fellow and predoctoral TEACHING fellows, although the move is to return to a combined, more generic, fellowship program.
Fellows are selected on a competitive basis. As a fellow you spend an extra year in the OMM department (3 four month long blocks) engaged in various academic, teaching, research, and clinical activities. There is the option to earn a Master's degree in public health through the School of Public Health as part of your fellowship program by completing specific requirements and writing a thesis or completing a problem-in-lieu of thesis (PILOT). This is not the same as the combined DO/MPH program (of which I'm in too).
Fellows get a tuition waiver if they are out-of-state residents, receive their third year of medical school paid for by the OMM department, receive a travel and book stipend, and are hired and reimbursed at the level of a quarter-time faculty position.
Fellows also get to see their own patients two days per week, under the supervision of board certified OMM and PM&R specialists, in the manipulative medicine clinic.
All in all, it's a great program, but a lot of work. It gives you a good taste of what being in academic medicine is all about. I'll be more than happy to answer any specific questions via personal e-mail.
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David Russo, MS3
UNTHSC/TCOM
StudentDoctor.Net Forum Moderator