You can authenticate to a Windows 2000 domain's ldap server easily by using the simplified netbios form of the username.

Somebody written:
When authenticating to a Win2k LDAP server, the name of the person must be
the FULL NAME in the dn 

NO. You can use this form:

$user = "DOMAINNAME\\username"
$password = "Password_of_user"; 

if (!$connect = ldap_connect("<server>", <port>)) { 
  //error
  exit;
} 
if (!$res = @ldap_bind($ldap, $user, $password)) { 
  //error
  exit;
} 

It works fine with Active Directory, we use it.