http://drupal.org/node/495654
http://dialogmix.com/drupal-panels-pane-theming-css
http://activelamp.com/blog/advanced-drupal-theming-using-panels-part-1-embracing-panels-style-plugins-and-writing-your-own
http://pt.scribd.com/doc/16183076/Styling-Theming-Panels-3-for-Drupal