//In my window.addEvent functions I've added the expandCollapse() function - the key is to add one div with an id of expand, and one with and id of collapse into the accordion div

window.addEvent('domready', function() {
	var accordion = new Accordion($$('.toggler'),$$('.element'), {
		opacity: 0,
		onActive: function(toggler) { toggler.setStyle('background', '#transparent url("img/collapse.gif") no-repeat 0% 45%'); },
		onBackground: function(toggler) { toggler.setStyle('background', '#transparent url("img/expand.gif") no-repeat 0% 45%'); }
	});	
	//make it open on hover  
	//$$('.toggler').addEvent('mouseenter', function() { this.fireEvent('click'); });  
});