Котик Антон

class iaComment
{

    // Метод можно сделать static
    static public function smileToSmile() {
        $smiles = array(
        ':)' => '<img alt=":)" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/smile.png">',
        '=)' => '<img alt="=)" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/smile.png">',
        ':(' => '<img alt=":(" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/sad.png">',
        '=(' => '<img alt="=(" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/sad.png">',
        ':D' => '<img alt=":D" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/happy.png">',
        ':\'(' => '<img alt=":\'(" src="' . IA_URL . 'plugins/comments/templates/front/img/smiles/cry.png">'
        );
        return array(array_keys($smiles), array_values($smiles));
    }

   // ...
}

// Получаем массив один раз (вне цикла), чтобы каждый раз не дёргать класс
$smiles = iaComment::smileToSmile();
foreach ($comments as &$comment) {
    $comment['body'] = str_replace($smiles[0], $smiles[1], $comment['body']);
}