- The official WordPress.org development blog is a must for WordPress updates and news.
- WPTavern.com is a great resource for the latest news in the world of WordPress.org development.
- WPShout.com, run by Alex Denning, is one of the best resources for WordPress theme development.
- WPhacks.com is run by Kyle Eslick and as the name suggests is about hacking WordPress :)
- WPCandy.com is a site on everything about WordPress, from the latest themes and plugins to tutorials and tips. Two resources worth checking out are the WordPress Help Sheet and the Advanced WordPress Help Sheet.
- WordPress Hooks Database - a great resource for a WordPress plugin developer. This database lists which hooks are available and in what version of WordPress.
- Adam R. Brown also has a PHP tutorial specifically for WordPress users.
- iThemes have list the items in a WordPress Developer Toolkit which lists a very useful useful code snippets cheatsheet amongst other things.
- WordPress Nexus contains a directory of WordPress resources.
