PHPBuilder.com has posted a new article (an excerpt from the "Foundations of PEAR" book from APress) focusing on the authentication aspect and components PEAR has to offer.

After all, nearly all authentication is identical in its basic functionality, and there's usually no good reason to spin off your own code if it's already written for you.

They talk about three packages - the Auth package, Auth_HTTP, and the Auth_PrefManager. They describe the Auth package in depth in this article - common uses, related packages, required packages, what the constructor is like and descriptions of the functions the package provides.