Magento: Get configurable product attributes

When dealing with configurable products.You need getTypeInstance() method.

1-For all available attribute options:

<?php
    $attrs  = $_product->getTypeInstance(true)->getConfigurableAttributesAsArray($_product);
    foreach($attrs as $attr) {
         $options    = $attr['values'];
         foreach($options as $option) {
            print "{$option['store_label']}<br />";
         }
    }
?>

2-For attribute code(color) options:

<?php
    $attrs  = $_product->getTypeInstance(true)->getConfigurableAttributesAsArray($_product);
    foreach($attrs as $attr) {
        if(0 == strcmp("color", $attr['attribute_code'])) {
            $options    = $attr['values'];
            foreach($options as $option) {
                print "{$option['store_label']}<br />";
            }
        }
    }
?>

3-For attribute code(size) options:

<?php
    $attrs  = $_product->getTypeInstance(true)->getConfigurableAttributesAsArray($_product);
    foreach($attrs as $attr) {
        if(0 == strcmp("size", $attr['attribute_code'])) {
            $options    = $attr['values'];
            foreach($options as $option) {
                print "{$option['store_label']}<br />";
            }
        }
    }
?>