I added a comment, but I think it can qualify for an answer as well. I have a little different view then some of the other comments already expressed.
In general SCM (Software Configuration Management) or (Source Code Management - derived term) it is easy to understand as it is used as an umbrella term which includes both revision control as well as other techniques like baseline management. See http://en.wikipedia.org/wiki/Software_configuration_management. In general modern SCM tools which range from CVS to Git include both of these techniques and many more useful features like: permission control, rights management, security auditing, allow customization of the SCM flow (ClearCase), integrate with build-system and issue tracking software, etc... I think the list is open because anything related to software change and management can enter here.
So the main confusion comes from understanding the difference between Revision Control, Version Control and possibly Source Control. First of all, all terms which include "source" are all derived terms, by that I mean some people are bothered by all these generic terms (configuration management - what's that?) and insist that they work with source code in particular and they don't care about other use-cases; which is fair point.
Regarding Revision Control vs Version Control I think the correct term (in context of tools like SVN, Git) is Revision Control. In my view, with the term Revision Control the emphasis is on managing the change (besides managing the versions) of the (not only) source code files, while with Version Control the emphasis falls on managing only the versions of the files.
In theory someone could write a piece of software which allows tracking and management of binary files with no binary diff and merging support and would call this Version Control System. However in case of tools like SVN, Git these additionally allow managing the changes to the files: diffing, merging and in case of Git the famous rebasing.
So in conclusion Revision Control includes Version Control and is more appropriate in naming tools like CVS, SVN, Git; while Source Control is a derived term and should be avoided if one would like to name a specific SCM aspect.
SCM > Revision Control > Version Control