If you don't have the multibyte extension installed, here's a function to decode UTF-16 encoded strings. It support both BOM-less and BOM'ed strings, (big- and little-endian byte order.)

<?php
/**
 * Decode UTF-16 encoded strings.
 * 
 * Can handle both BOM'ed data and un-BOM'ed data. 
 * Assumes Big-Endian byte order if no BOM is available.
 * 
 * @param   string  $str  UTF-16 encoded data to decode.
 * @return  string  UTF-8 / ISO encoded data.
 * @access  public
 * @version 0.1 / 2005-01-19
 * @author  Rasmus Andersson {@link http://rasmusandersson.se/}
 * @package Groupies
 */
function utf16_decode( $str ) {
    if( strlen($str) < 2 ) return $str;
    $bom_be = true;
    $c0 = ord($str{0});
    $c1 = ord($str{1});
    if( $c0 == 0xfe && $c1 == 0xff ) { $str = substr($str,2); }
    elseif( $c0 == 0xff && $c1 == 0xfe ) { $str = substr($str,2); $bom_be = false; }
    $len = strlen($str);
    $newstr = '';
    for($i=0;$i<$len;$i+=2) {
        if( $bom_be ) { $val = ord($str{$i})   << 4; $val += ord($str{$i+1}); }
        else {        $val = ord($str{$i+1}) << 4; $val += ord($str{$i}); }
        $newstr .= ($val == 0x228) ? "\n" : chr($val);
    }
    return $newstr;
}
?>