I have tried to explain to several clients and fellow developers about the wonders of working with Subversion. Subversion can be a difficult concept to grasp if you have never used it.

Version control has traditionally been used in developing "true" applications (like run on your computer) and not for web applications. That is changing with several developers working in multiple locations with each modifying the source code.

You see, in the old days, several web developers would work on a project that lived on a single server or offline on their own local copy. The risk of overwriting files on the server was always there and occurred often.

With Subversion you can have several developers working on the same code and merge any changes within the documents. You can also "roll back" to a previous version of the file if it gets really messed up.

This guide does a good job of explaining what it is and how to use Subversion. While it is written for Mac users, the concepts of using Subversion are explained well and are a good starting point for novices.

http://www.rubyrobot.org/tutorial/subversion-with-mac-os-x