Do you ever wish that you could style a specific breadcrumb in Drupal's breadcrumb trail? Well, you can. Drupal's handy theme_ functions allow you to selectively override any function that constructs a themed element.
To theme your breadcrumbs, use the theme_breadcrumb function. Simply add a new function to your template.php following this naming convention: [your_themes_machine_name]_breadcrumb. Take a look at my customized breadcrumb function for the "grasmash" theme. It does the following: