How can i echo the featured image url?

Nevermind, I figured it out. For anyone else who is stuck, this is how I got to my result.

<?php query_posts('showposts=1&category_name=topstories&offset=3'); ?>
<?php while (have_posts()): the_post(); ?>  

<?php $attachments = get_children( array('post_parent' => get_the_ID(), 'post_type' => 'attachment', 'post_mime_type' =>'image',  'showposts' => 1) );
foreach ( $attachments as $attachment_id => $attachment ) {
echo wp_get_attachment_url( $attachment_id, 'medium' ); } ?>

<?php endwhile; ?>