From my handbook page on d.o

This little code snippet will add the present page title to the
breadcrumb. We show you how to use this in steps.

Step 1 : If you do not have a template.php file in
your sites/all/themes/yourtheme/ folder, create one.

Step 2 : Copy and paste this code in the
template.php file.

{syntaxhighlighter brush: php;fontsize: 100; first-line: 1; }function phptemplate_breadcrumb($breadcrumb){
if (!empty($breadcrumb)) {
$breadcrumb[] = drupal_get_title();
return '<div class="breadcrumb">'. implode(' » ', $breadcrumb) .'</div>';
}
}{/syntaxhighlighter}Remember to clear the cache or theme registry to let drupal know of this new theme function.