$node=node_load(arg(1));
$nids=array();
if($node && $node->taxonomy) {
  foreach($node->taxonomy as $term) { 
    $result = db_query("SELECT nid from {node} where title='".$term->name."'");
    while ($row = db_fetch_object($result)) {
      $nids[] = $row->nid;
    }
  }
  return implode('+',$nids);
} else { 
  return;
}