PHP is probably the most used scripting language behind the internet. So taking a hint from last weeks list, we point to Smashing Magazine and their Advanced PHP Tips. Don't worry if you're a beginner, these tips are a good starting point for anyone interested in learning (and so is Webmonkey's PHP Tutorial for Beginners, ahem).
Our favorite tips? Database injections can be a pain. The SQL Injection cheat sheet will help. Speed up your website with Memcached. The list even mentions some popular frameworks, like CakePHP and Solar, that will help take care of some of the legwork for you.
[Updated 3/31. Whoops! Broken link. Thanks @Arlen]
