Easy CC License is a WordPress plugin by MakerBlock that creates a WordPress shortcode for adding Creative Commons license information to your posts. All you have to do is use the shortcode [ezcc] in any post and the plugin does the rest. The plugin also gives you the option of including a Creative Commons license at the end of every post, every page, or every post and page.
The author says “This plugin comes with an uninstall feature, so it won’t leave any trace in your database after it has been uninstalled. It also caches your license settings so that it doesn’t slow down your website with unnecessary calls to the Creative Commons API. It doesn’t create extra tables, content types, or taxonomies.”