Getting source code via CVS
Apple's public source projects are available via CVS as well as the web. CVS is generally a better way for developers to obtain our sources, in comparison to downloading a released source archive for a number of reasons:

You get access to all versions.
Only released versions of the code are available in source archives. If you would like to see the very latest code, you'll need to use CVS. Additionally, CVS allows you to view all version of each file in a project, and provides a mechanism to view specifically what changed with each version.

You get access to change logs.
As we made changes, we put useful comments in the CVS logs which describe what changes were made and why.

You use less bandwidth.
Once you have obtain a full copy of the code, only the changes made since then are sent to you when you request an update; you needn't pull down the entire source tree again.

What is CVS?
CVS is the Concurrent Versions System. It is a source control tool which allows multiple people to simultaneously view and edit code.

CVS keeps a history of all changes that have been made to the code, along with who made the change and when it was committed into the repository.

Getting and using CVS
Learn how to get CVS, some basic concept about how it works, how to started with using CVS, and where to get more information about it.