For thoes of you who're looking to generate an NTLM hash (not an LM hash), I found out it's quite simple..

It uses the basic MD4 function, but the password needs to be in Unicode Little Endian encode first (this canbe achieved by the iconv function).

This can be done easily by using the following code:

<?php
function NTLMHash($Input) {
  // Convert the password from UTF8 to UTF16 (little endian)
  $Input=iconv('UTF-8','UTF-16LE',$Input);

  // Encrypt it with the MD4 hash
  $MD4Hash=bin2hex(mhash(MHASH_MD4,$Input));

  // You could use this instead, but mhash works on PHP 4 and 5 or above
  // The hash function only works on 5 or above
  //$MD4Hash=hash('md4',$Input);

  // Make it uppercase, not necessary, but it's common to do so with NTLM hashes
  $NTLMHash=strtoupper($MD4Hash);

  // Return the result
  return($NTLMHash);
}
?>

To produce an LM hash requires a fully-written script containing the algorithm used to make it.

Enjoy,
CraquePipe.

And some code for LM hash:

<?php
function LMhash($string)
{
    $string = strtoupper(substr($string,0,14));

    $p1 = LMhash_DESencrypt(substr($string, 0, 7));
    $p2 = LMhash_DESencrypt(substr($string, 7, 7));

    return strtoupper($p1.$p2);
}

function LMhash_DESencrypt($string)
{
    $key = array();
    $tmp = array();
    $len = strlen($string);

    for ($i=0; $i<7; ++$i)
        $tmp[] = $i < $len ? ord($string[$i]) : 0;

    $key[] = $tmp[0] & 254;
    $key[] = ($tmp[0] << 7) | ($tmp[1] >> 1);
    $key[] = ($tmp[1] << 6) | ($tmp[2] >> 2);
    $key[] = ($tmp[2] << 5) | ($tmp[3] >> 3);
    $key[] = ($tmp[3] << 4) | ($tmp[4] >> 4);
    $key[] = ($tmp[4] << 3) | ($tmp[5] >> 5);
    $key[] = ($tmp[5] << 2) | ($tmp[6] >> 6);
    $key[] = $tmp[6] << 1;
   
    $is = mcrypt_get_iv_size(MCRYPT_DES, MCRYPT_MODE_ECB);
    $iv = mcrypt_create_iv($is, MCRYPT_RAND);
    $key0 = "";
   
    foreach ($key as $k)
        $key0 .= chr($k);
    $crypt = mcrypt_encrypt(MCRYPT_DES, $key0, "KGS!@#$%", MCRYPT_MODE_ECB, $iv);

    return bin2hex($crypt);
}
?>

Some optimization?

For Samba ueserPassword you can use:

(I am not very sure aboute the salt part, but it works for me like that)

<?php
function CRYPThash($string, $salt = null)
{
    if (!$salt)
        $salt = rand(10,99);
    
    return "{CRYPT}".crypt($string, $salt);
}
?>

In posted NTLMHash function you can also use:

<?php
// Encrypt it with the MD4 hash
$MD4Hash=hash('md4',$Input);
?>

So you don't need to install mhash libraries

Note for FreeBSD with PHP-5. 

This is disabled by default; use the security/php5-hash port:
cd /usr/ports/security/php5-hash ; make install clean
(do not use the security/pecl-hash port as in the past, see the /usr/ports/UPDATING post from 20081211)