New from Builder.com is a two-part series on discovering the finer points of the php.ini file - Part 1 and Part 2.

The first part starts out introducing you to the php.ini file - what it's for, what it can do for you, and how to get about adjusting settings to help you (and your code) out for better performance. They highlight a few items, showing how they can speed up your code and help you catch errors.

Part 2 gets into working with extensions, the benefits of some of the security settings (i.e. safe_mode) as well as working with file uploads, more performance tweaking and how to set these values from your script instead of the actual php.ini file (ini_set).

These are both a good overview, but there's still a lot to be covered for anyone seriously looking to optimize their php.ini...