var i = 0;
var slide;

function SlideShow() {
        $( slide[i] ).fade({ duration:5 });
        i++;            
        if (i == slide.length) i = 0; 
        $( slide[i] ).appear({ duration:5, afterFinish: function () { SlideShow(); } });
} 

document.observe('dom:loaded', function () {
        $$('#slideshow img').each(function(image){
                $(image).hide();
        });
        slide =  $('slideshow').childElements();
        $( slide[0] ).appear({ duration:1, afterFinish: function () { SlideShow(); } });
});