This is the most drop-dead simple jQuery slideshow you could possibly have. Nothing fancy at all, but mind-boggling get-out-of-the-way simple. Actually using it for a client project.

index.html

<div id="slider">
  <img>
  <input type="hidden" value="/wp-content/themes/geek/images/slide1.png">
  <input type="hidden" value="/wp-content/themes/geek/images/slide2.png">
  <input type="hidden" value="/wp-content/themes/geek/images/slide3.png">
  <input type="hidden" value="/wp-content/themes/geek/images/slide4.png">
</div>

slider.js

jQuery(document).ready(function( $ )
{
	var i = 0;
	var url = $('#slider input');
	function slide()
	{
		$('#slider img').attr('src', $(url[i]).val() );
		i >= $('#slider input').length - 1 ? i = 0 : i++;
	}
	setInterval(slide, 7000);
	slide();
});