From time to time everyone finds them selves in a position where they are faced with a scenario they have never encountered before. Tonight I was attempting to get all orders for a customer based on the customer email address.. While there are probably several ways to do this, I found a nice query that is quick, and efficient.
$orderCollection = Mage::getModel('sales/order')->getCollection();
Happy coding, hope this helps next time you're working on Magento