The process of adding a button to the wordpress editor is straight enough if you follow the instructions that there is in the WordPress Codex and in the the tinyMCE editor documentation. The first one explain how to hook into WordPress to define the name of your tinyMCE plugin and the path to the javascript that the editor calls. The second one define how to build that javascript.
via Adding a select box to WordPress tinyMCE editor | javimarque.
Tags: javascript, Plugins, Wordpress