Full Breadcrums, how to?

Hi there, I'm trying to get a full breadcrumb in my theme, so it will be like this: Home > Parrent Category > Sub Category > Product.

Ive tried to make abit of a function but the the_category doesnt work, heres what ive made:

function the_breadcrumb() {
	if (!is_home()) {
		echo '<a href="';
		echo get_option('home');
		echo '">';
		echo "</a> » ";
		if (is_category() || is_single()) {
			if (is_single()) {
				echo " » ";
		} elseif (is_page()) {
			echo the_title();

If any1 got a piece of code or can help me build my own that would be great. Cheers