It is possible to configured the list of font’s names to be displayed in the Font combo in the toolbar. To do this you will need to simply configure the 'config.js' file.

This is found at:-

plugins/editors/jckeditor/config.js

You can define new fonts by adding a new parameter to the config.js file as detailed below:-

config.font_names = 'Arial;Times New Roman;Verdana';

Example:-

/*
Copyright (c) 2003-2010, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

CKEDITOR.editorConfig = function( config )
{
    // Define changes to default configuration here. For example:
    // config.language = 'fr';
    // config.uiColor = '#AADC6E';
    config.toolbar_Image =
    [
        ['ImageManager']
    ];

    config.removePluginsForFullScreenMode = ['Source','Preview','Cut','Copy','Paste','Undo','Redo','SelectAll','RemoveFormat','Bold','Italic',
                                            'Underline','Strike','Subscript','Superscript','NumberedList','BulletedList','Outdent','Indent',
                                            'JustifyLeft','JustifyCenter','JustifyRight','JustifyBlock','ImageManager','imagesearch','HorizontalRule','filebrowser','imgMap'];
    
   config.font_names = 'Arial;Times New Roman;Verdana';
    
};

For more info please see: http://docs.cksource.com/ckeditor_api/symbols/CKEDITOR.config.html#.font_names