<crontab>
        <jobs>
            <webtex_giftcards_send_email_by_delivery_date>
                <schedule>
                    <cron_expr>0 1 * * *</cron_expr>
                </schedule>
                <run>
                    <model>giftcards/observer::sendEmailByDeliveryDate</model>
                </run>
            </webtex_giftcards_send_email_by_delivery_date>
        </jobs>
    </crontab>

/**
     * Send email based on delivery date specified by customer
     * starts every day at 01.00 am (see config.xml)
     */
    public function sendEmailByDeliveryDate()
    {
        $currentDate = date('Y-m-d');
        $oGiftCards = Mage::getModel('giftcards/giftcards')->getCollection()
            ->addFieldToFilter('mail_delivery_date', array('eq' => $currentDate))
            ->addFieldToFilter('card_status', 1);
        foreach ($oGiftCards as $oGiftCard) {
            $oGiftCard->send();
        }
    }