http://www.magentocommerce.com/boards/v/viewreply/89946/
http://stackoverflow.com/questions/4588824/mass-update-magento-field-to-use-default-value
http://stackoverflow.com/questions/9299145/magento-save-a-product-without-setting-use-default-value
http://stackoverflow.com/questions/9302279/magento-setting-product-attributes-use-default-value-using-updateattributes
http://stackoverflow.com/questions/8361030/save-use-default-value-for-these-magento-attributes
http://stackoverflow.com/questions/7120070/how-to-enable-use-default-value-for-product-attribute-programmatically
http://blog.goods-pro.com/1642/magento-code-snippet/ (might be something good here)