Within our organization, we identified two groups of SCM "consumers," and tailored our training to each of those groups.
SCM Coordinators are expected to know not only what we do with SCM, but why we do it. There's an expectation that they understand our branching methodology, and that they know how to do merges within the tool and at the command line. They are our first line of defense in the development trenches.
Developers are expected to know how to "get", "check out," and "commit." They should have a high level understanding of our branching methodology so they know which branches to work in, and they need to know how to use the integrated SCM UI to interact with the repository.
Our SCM Coordinators were somewhat hand-picked senior people, and we gave (and continue to give) them close one-on-one assistance to help them learn.
Our Developers get a PowerPoint deck and (hopefully) some one-on-one time with their SCM Coordinator. I think the developer PowerPoint deck is about 15 pages of 18-point type.
Thus far, this has worked out pretty well. My main recommendation is to make sure you don't overwhelm people with the SCM details if they don't need to know it. I've noticed the average person glazes over and dozes off within about 5 minutes of SCM discussion.