Below is a Prezi presentation I have put together which I have used in introductory sessions and when presenting our college e-portfolio, Mahara, to our senior managers and executive staff. Although it is Mahara specific, it mentions some general points which are applicable to the role-out of any e-portfolio system.
The main thing I have tried to get across is the difference between Moodle (our VLE) and Mahara in terms of ownership and who gets to see what. This seems to be something people struggle to get their heads around. I found the Appendix chapter: Mahara Implementation Pre-Planner (from the Mahara 1.2 ePortfolios book) a really useful resource when thinking about how we might implement e-portfolios.