The following book from the UK (edited by two of my colleagues) might have provide some useful leads:
Hyde, R. & Edwards, J. (Eds.) (2013). Mentoring mathematics teachers: supporting and inspiring pre-service and newly-qualified teachers. Abingdon, UK: Routledge.
I think you might find Lesson Study a helpful method. Here's a link to a nice podcast on it by American Radio Works called, "Teaching Teachers" http://www.americanradioworks.org/documentaries/teaching-teachers/