I usually save the list for the Twitter feed, but while I've been playing around with PHP lately, thanks to a new Drupal installation, I've reawakened to the fact that PHP is the duct tape of the web. It works on practically every web server and is typically the starting point for developers interested in writing their first web application.
This week's list of the week points to Noupe who mustered together 20 Useful PHP Components and Tutorials for Everyday Projects.
Among the most useful are framework tools for secure forms, login systems and manipulating APIs such as those from Google and Twitter.
One particular favorite I didn't know about before, and number one on the list, is pChart; a framework for creating charts and data-driven graphics dynamically.