Get users by term id
There isn't, but since users are entities, and taxonomy term references are fields, you can use an EntityFieldQuery to get this data. You could even wrap it in a function to make your life very easy:

function taxonomy_select_users($term_id) {
  $query = new EntityFieldQuery;
  $query-&gt;entityCondition('entity_type', 'user')
    -&gt;fieldCondition('field_taxonomy_term_field', 'tid', $term_id);

  $results = $query-&gt;execute();

  if (isset($results['user'])) {
    return user_load_multiple(array_keys($results['user']));    
  }

  return FALSE;
}