functions.php

<?php
/* add everything below here to the themes functions.php file */

add_filter( 'the_password_form', 'custom_password_form' );
function custom_password_form() {
	global $post;
	$label = 'pwbox-'.( empty( $post->ID ) ? rand() : $post->ID );
	$o = '<form class="protected-post-form" action="' . get_option('siteurl') . '/wp-pass.php" method="post">
	' . __( "This post is password protected. To view it please enter your password below:" ) . '
	<label for="' . $label . '">' . __( "Password:" ) . ' </label><input name="post_password" id="' . $label . '" type="password" size="20" /><input type="submit" name="Submit" value="' . esc_attr__( "Submit" ) . '" />
	</form>
	';
	return $o;
}