PHP best practices for user authentication and password security

Question

What are the best current libraries/methods to authenticate users without the use of a CMS or heavy framework?

Responses should include suggestions for anything you

Answer 1

OpenID is a method to authenticate users based on their existing accounts on common web services such as Yahoo, Google and Flickr.

Logins to your site are based on a successful login to the remote site.

You do not need to store sensitive user information or use SSL to secure user logins.

A current PHP version of the library can be found here.