DELCA.RU

// Из Unicode в UTF-8
function unicode_decode($str){
    return preg_replace("/\\\u([0-9A-F]{4})/ie", "iconv('utf-16', 'utf-8', hex2str(\"$1\"))", $str); 
}
function hex2str($hex) {
    $r = '';
    for ($i = 0; $i < strlen($hex) - 1; $i += 2)
    $r .= chr(hexdec($hex[$i] . $hex[$i + 1]));
    return $r;
}
unicode_decode('\u0410'); // Вернет "А"