// MySQL table:
+----+--------+-------+
| id | parent | name  |
+----+--------+-------+
|  1 |      0 | test  |
|  2 |      0 | test1 |
|  3 |      1 | test2 |
|  4 |      1 | test3 |
|  5 |      2 | test4 |
|  6 |      0 | test5 |
|  7 |      2 | test6 |
|  8 |      3 | test7 |
+----+--------+-------+
8 rows in set (0.00 sec)

// code
<?php
function getConnection()
{
    $user = 'user';
    $host = 'localhost';
    $password = 'pass';
    $database = 'test';
    $cn = mysql_connect($host,$user,$password);
    mysql_select_db($database,$cn);
    return $cn;
}

function display_nodes($parent)
{
    $cn = getConnection();
    $query = "SELECT a.id, a.parent, a.name FROM `menu` a WHERE parent = $parent";
    $result = mysql_query($query,$cn);
    echo "<ul>";
    while($record = mysql_fetch_assoc($result))
    {
        if(has_children($record['id']))
        {
            echo "<li>{$record['name']}";
            display_nodes($record['id']);
            echo "</li>";
        }
        else
        {
            echo "<li>{$record['name']}</li>";
        }
    }
    echo "</ul>";
}

function has_children($parent)
{
    $cn = getConnection();
    $query = "SELECT COUNT(*) AS count FROM `menu` WHERE parent = {$parent}";
    $result = mysql_query($query,$cn);
    $record = mysql_fetch_assoc($result);

    if($record['count'])
        return true;
    else
        return false;
}

display_nodes(0);

// resutl:
    * test
          o test2
                + test7
          o test3
    * test1
          o test4
          o test6
    * test5