source version/revision control software

strictly speaking, it is not my line of business.  but implementation of a SVC is related to governance, audit, and security objectives.  a few quick links:

wikipedia: software configuration management,  revision control, and comparison of revision control software.

osswatch on version control.

betterexplained: a visual guide to version control.

version control from the book producing open source software. 

smashing magazine: top 7 OS-VCS

and more links on pressman's site.