Programmatically retrieve list of all shipping methods

Question

I\'m writing a quick-and-dirty module to restrict shipping methods based on products in the cart. For example, if the customer adds food, I only want overnight shipping met

Answer 1

I've created a function for this out of the answers already provided. This creates an option group of all the shipping methods:

function getShippingMethods($_methods, $fieldId, $fieldName, $fieldClass){
    $_shippingHtml = '';
    foreach($_methods as $_carrierCode => $_carrier){
        if($_method = $_carrier->getAllowedMethods())  {
            if(!$_title = Mage::getStoreConfig('carriers/' . $_carrierCode . ' /title')) {
                $_title = $_carrierCode;
            }
            $_shippingHtml .= '';
            foreach($_method as $_mcode => $_m){
                $_code = $_carrierCode . '_' . $_mcode;
                $_shippingHtml .= '' . $_m . '';
            }
            $_shippingHtml .= '';
        }
    }
    $_shippingHtml .= '';
    return $_shippingHtml;
}

The $_methods argument is an object from Magento:

$_methods = Mage::getSingleton('shipping/config')->getActiveCarriers();

So, we can call the function and pass the $_methods object to it as follows:

Hope that helps someone else.