Adding an "author" dropdown to the Media Uploader

wp-media_author.php

<?php
// Just an example. Probably doesn't work.

add_filter('attachment_fields_to_edit', 'add_media_author_field', 10, 2);
add_filter('attachment_fields_to_save', 'save_media_author'), 10, 2);

function add_media_author_field($fields, $post) {
	// add the dropdown to $fields
	$fields['media-author'] = array(
		'label' => __('Credit:'),
		'input' => 'html',
		'html' => wp_dropdown_users( array( 'echo' => 0 );
	);
	return $fields;
}

function save_media_author($post, $attachment) {
	$attachment->post_author = $_POST('media_author');
	return $post;
}
?>