Here's some reading for me to do some time soon...
http://www.webreference.com/js/column79/
http://www.webreference.com/js/column80/
http://w3future.com/html/stories/hop.xml
http://w3future.com/html/stories/callbacks.xml
http://w3future.com/html/loell/
http://jibbering.com/faq/faq_notes/closures.html