How to show category description?

Do you find wordpress will now show category descriptions if you use default themes? Here is the method:

<div><?php echo category_description( $category ); ?></div>
<?php }
at the end of header.php or footer.php
If you use other themes, and you still can not find the categories description, the you can add the code:

1.Open up category.php if you have it, and archive.php if you don’t.
2. Add the above code the proper position.