Extending Magento Shopping Cart

Question

I need to extend the Magento shopping cart to include an extra step for a store locator. I understand that I need to overwrite the core OnePage controller (Mage_Checkout_O

Answer 1

Here is a complete working module.. its (almost) the same as the above code of Johnatan. You will find it here: https://bitbucket.org/vovsky/adding-custom-product-attribute-to-quote-and-order-items-in/

And full explanation of every step here: http://www.atwix.com/magento/custom-product-attribute-quote-order-item/