Isto irá fazer o truque. De sua pergunta, suponho que o cliente já tenha selecionado o método de envio desejado.
<?php
$quote = Mage::getModel("checkout/session")->getQuote();
$amount = $quote->getShippingAddress()->getShippingAmount();
De fato, existem vários métodos disponíveis para você. Tal como:
<?php
$address = $quote->getShippingAddress();
$address->getBaseShippingAmount();
$address->getBaseShippingDiscountAmount();
$address->getBaseShippingHiddenTaxAmount();
$address->getBaseShippingInclTax();
$address->getBaseShippingTaxAmount();
$address->getShippingAmount();
$address->getShippingDiscountAmount();
$address->getShippingHiddenTaxAmount();
$address->getShippingInclTax();
$address->getShippingTaxAmount();
Se você simplesmente deseja obter todas as taxas de remessa disponíveis em uma matriz:
<?php
$address = $quote->getShippingAddress();
$shippingPrices = array();
foreach($address->getAllShippingRates() as $rate){
$shippingPrices[$rate->getCode()] = $rate->getPrice();
}
var_dump($shippingPrices);