How does PAM Authentication Work?
Im definately no expert on PAM but I do know a little about it. It is really almost transparent even for the admin, once it is setup. I use it because I like the logging and it is very easy to setup. You can have each service log and authenticate differently. And I think that most distros use PAM by default so you never even have to touch it. If you have any specific questions about it then reply back and I might be able to help with them.