The Custom Content Type Manager (or CCTM) plugin allows WordPress 3.x users to create, extend, and manage custom content types (a.k.a. post types) and their fields like a true CMS. You can define custom fields for any content type, including checkboxes, textareas, and dropdowns. Developers can also create their own types of fields.
Custom fields can be added to any post type so that each time you create a new post, page, book, or movie post, a standard set of user-defined fields will be there. Custom field can hold any type of information: dropdown lists, checkboxes, WYSIWYG, and even images.
This is the Github home for plugin for WordPress. The code was ported to Github after Google Code announced that it will be shutting down in 2015. The legacy code-base is still visible at https://code.google.com/p/wordpress-custom-content-type-manager/