Check out this recent publication by the GSU Sociology Department Senior Lecturer & Director of Instruction Mindy Stombler, and graduated doctoral students Amanda Jungels, Marni Brown, and Saori Yasumoto:
Jungels, A. M., Brown, M. A., Stombler, M., & Yasumoto, S. (2014). Teaching Associates: Bridging informal and formal mechanisms of support for graduate student instructors. Teaching Sociology, 42(3), 220-230.
Jungels et al. draw on data collected from focus groups, semistructured interviews, and surveys to explore how the graduate “Teaching Associate” in the GSU Sociology Department acts as a formal and informal teaching mentor for the other graduate student instructors to prepare them for effective teaching in their present positions and beyond as future faculty. They conclude with recommending the Teaching Associate model to other sociology departments.