var slideSpeed = 3000;
var fadeSpeed = 'slow';
var $slideshow = $('.slideshow').children().not(':first').hide().end().end();

setTimeout(next, slideSpeed);

function next() {
    var el = $slideshow.children(':visible');

    if (el.next().length > 0) {
        el.next().fadeIn(fadeSpeed).end().fadeOut(fadeSpeed);
    }
    else {
        $slideshow.children(':first').fadeIn(fadeSpeed);
        el.fadeOut(fadeSpeed);
    }

    setTimeout(next, slideSpeed);
}