On NetTuts.com today there's a new tutorial from Burak Guzel about keeping your passwords (and web applications) safer by using hashing with passwords and understanding which of the PHP functions is right for you.

From time to time, servers and databases are stolen or compromised. With this in mind, it is important to ensure that some crucial user data, such as passwords, can not be recovered. Today, we are going to learn the basics behind hashing and what it takes to protect passwords in your web applications.

The article is a simple introduction to the topic and doesn't claim that it will protect you 100% but it's good to get the ball rolling. They talk about md5 hashing and the crypt method. He also outlines a few problems that surround hashing - hash collisions, attackers using "rainbow tables" and how quickly the average computer can run through hashes (an average 8 character password could be broken in around 60 hours). For each, he includes a few things you can do in your code to help prevent them from happening.