jquery

http://roshanbh.com.np/2008/03/make-accordion-using-jquery.html

http://net.tutsplus.com/tutorials/javascript-ajax/create-a-simple-intelligent-accordion-effect-using-prototype-and-scriptaculous/

http://www.switchonthecode.com/tutorials/javascript-and-css-tutorial-accordion-menus

http://www.leigeber.com/2008/04/lightweight-javascript-and-css-accordion/