Create a Drupal user programatically

gistfile1.php

require_once DRUPAL_ROOT . '/' . variable_get('password_inc', 'includes/password.inc');
$account->name = 'user_name';
$account->pass = user_hash_password('password_string');
$account->mail = 'user@mail.com';
$account->status = 1;
// Add Role with rid 3 to this user
$roles = array('3' => true);
$account->roles = $roles;

$user = user_save($account);