Custom post type for People in WP. Includes dropdown of existing users to associate to the person post.

people_post_type.php

<?php

/**
 * Custom Post Type for People
 */
function people_register_post_types() {
    register_post_type( 'people',
        array(
            'labels' => array(
                'name' => __( 'People' ),
                'singular_name' => __( 'Person' )
              ),
              'capability_type' => 'post',
            'public' => true,
            'supports' => array( 'title', 'editor', 'thumbnail'),
            'menu_position' => 20,
            'hierarchical' => false,
            'has_archive' => true,
            'show_in_nav_menus' => true,
            'rewrite' => array('slug' => 'people')
        )
    );
}

add_action( 'init', 'people_register_post_types' );

/**
 * Adds our post meta boxes for the 'sp_workshop' post type.
 */
function people_add_meta_boxes() {
    add_meta_box("wp-user-information", __('Personal Info'), "people_meta_box", "people", "advanced", "high");
}

add_action( 'admin_init', 'people_add_meta_boxes');

function people_meta_fields() {
  return array('person_title', 'person_email', 'person_phone', 'person_twitter', 'person_url', 'person_user_id');
}
/**
 * Meta box for personal information.
 */
function people_meta_box(){
    global $post;
    $custom = get_post_custom($post->ID);
    
    $fields = people_meta_fields();
?>

<?php foreach ($fields as $field): if ($field == 'person_user_id') continue; ?>
    <p><label for="<?php echo $field; ?>"><?php echo ucwords(str_replace('person_', ' ', $field)); ?></label></p>
    <p><input type="text" value="<?php echo @$custom[$field][0]; ?>" name="<?php echo $field; ?>" /></p>
<?php endforeach; ?>
    <p><label for="person_user_id">User</label></p>
      <p><?php wp_dropdown_users(array('name' => 'person_user_id', 'selected' => @$custom['person_user_id'][0])); ?></p>      
<?php
}

/**
* Saves our custom post metadata. Used on the 'save_post' hook.
*/
function people_save_post(){
  global $post;
  $fields = people_meta_fields();
  foreach ($fields as $field) {
    if ( array_key_exists($field, $_POST)) {
        update_post_meta($post->ID, $field, $_POST[$field]);
    }
  }

}

add_action( 'save_post','people_save_post');