The Custom Content Type Manager (CCTM) is a plugin written for WordPress 3.x. It allows WordPress 3.x users to create, extend, and manage custom content types (a.k.a. post types) like a true CMS. You can define and standardize custom fields for any content type, including checkboxes, textareas, and dropdowns.
Download the Custom Content Type Manager plugin from the WordPress site.
Visit the Official Page for the most up-to-date documentation.
Comments on this page have been closed — thanks to everyone who contributed; I felt that this page was getting a bit out of control. What we need is a forum, so I set up a forum for the CCTM project here: http://wordpress.org/support/plugin/custom-content-type-manager.
Please file all bugs here. It’s much easier for me to track them there. This site will be used to house tutorials and videos about the plugin.