show anonymous users in a view
There is (and should only ever be) one anonymous "user" for your site.  That will be in your db users table as uid 0.  

If you'd like to count the number of anonymous users that are visiting your site at a certain time you can adapt (to a custom module) something like this that is used in the admin_menu module (this is from admin_menu.module 7.x.3.0-rc starting around line 395:

function admin_menu_get_user_count() {
  $interval   = REQUEST_TIME - variable_get('user_block_seconds_online', 900);
  $count_anon = admin_menu_session_count($interval, TRUE);
  $count_auth = admin_menu_session_count($interval, FALSE);

  return t('@count-anon / @count-auth', array('@count-anon' =&gt; $count_anon, '@count-auth' =&gt; $count_auth));
}

function admin_menu_session_count($timestamp = 0, $anonymous = TRUE) {
  $query = db_select('sessions');
  $query-&gt;addExpression('COUNT(sid)', 'count');
  $query-&gt;condition('timestamp', $timestamp, '&gt;=');
  $query-&gt;condition('uid', 0, $anonymous ? '=' : '&gt;');
  return $query-&gt;execute()-&gt;fetchField();
}


And then output the return values. If you want to count the all time number of anon visits to your site than that is a different story. If so, please update. Thanks.