I'm familiar with adding custom meta boxes to my post types in WordPress but this is something I've not had to do before. I want to be able to select a user from a dropdown (in a metabox) and have that value saved with the post.

Here's my code:

    function add_users_meta_box() {  
    add_meta_box(  
        'users_meta_box', // $id  
        'Assign to user', // $title  
        'show_users_meta_box', // $callback  
        'property', // $page  
        'side', // $context  
        'high'); // $priority  
}  

add_action('add_meta_boxes', 'add_users_meta_box');

function show_users_meta_box() {
    wp_dropdown_users(array('name' => 'author', 'show_option_none' => '-- None --','selected' => $user_id));
}

Is it possible to extend this to both save the value and when the user re-opens the post to edit, have the position of the dropdown saved.

If anyone could point me in the right direction it would be much appreciated.