Magento layout xml / magento xml layout

http://magebase.com/magento-tutorials/demystifying-magentos-layout-xml-part-1/
http://magebase.com/magento-tutorials/digging-deeper-into-magentos-layout-xml-part-2/

5 Useful Tricks For Your Magento local.xml
http://magebase.com/magento-tutorials/5-useful-tricks-for-your-magento-local-xml/

Creating Custom Layout Handles
http://magebase.com/magento-tutorials/creating-custom-layout-handles/