There is a plugin called Latest Post By Category that does something similar to this
if (is_category()) {
$this_category = get_category($cat);
}
if ($this_category->category_parent) {
$child_categories = get_categories('child_of=' . $this_category->cat_id);
foreach ($child_categories as $child_category) {
$my_posts = get_posts('orderby=menu_order&order=ASC&cat=' . $child_category->cat_id);
foreach ($my_posts as $post) : the_post()
?>
<div class="post">
<?php the_title(); ?>
</div>
<?php endforeach; ?>
<?php } ?>
<?php } ?>
That code doesn’t quite work…but maybe it’s on the right track? Any ideas?
Thanks!