While working on picporta we had one requirement where were supposed to clone records within the same table.
Searching in MYSQL manual i found INSERT-SELECT statement but it still does not supports same table
So did this quick hack in PHP ..
$tempTable = mysql_fetch_array(mysql_query("SELECT * FROM table." WHERE id='$passedId'),MYSQL_ASSOC) or die("Could not select record");
$result = mysql_query("INSERT INTO table (".implode(", ",array_keys($tempTable)).") VALUES ('".implode("', '",array_values($tempTable))."')");
Worked for me ..