wp-admin/edit-tags.php?taxonomy=category
Just make sure the category and slug have different names. The category will be listed on the sidebar (by default template tags) and the slug will be in the url.
If you had the category titled teens, listed on the sidebar, but when you click the link, you want something different, change the slug, it will take you too an address such as
www.yoursite.com/category/randomteens/