<?php
 
$query = mysql_query("SHOW TABLE STATUS WHERE name='your_table_name_here'");
if (mysql_num_rows($query)) {
	$result = mysql_fetch_assoc($query);
	echo $result['Auto_increment'];
} else {//error
	//error control here
}
 
?>

<?php
 
function get_next_value($tablename) {
	$query = mysql_query("SHOW TABLE STATUS WHERE name='".mysql_real_escape_string($tablename)."'");
	if (mysql_num_rows($query)) {
		$result = mysql_fetch_assoc($query);
		return $result['Auto_increment'];
	} else {//error
		return false;
	}
}
 
//usage
$nextval = get_next_value('your_table_name_here');
 
?>