JavaScript Mouse Over Pause

I am really getting frustrated with my JS slideshow, I am trying to implement a mouse-over pause function in the slideshow. All I need the slideshow to do is pause when the user hovers over the slide. Seems easy right?! No, I have tried incorporating different functions but nothing seems to stick with the code.

<script type="text/javascript">// <![CDATA[
var imgs1 = new Array("http://ift.tt/1RmlUJb","http://ift.tt/1SwnYN5","http://ift.tt/1RmlTop","http://ift.tt/1SwnYN9");
var lnks1 = new Array("http://ift.tt/1RmlTor","http://ift.tt/1MPJYkh","http://ift.tt/1RmlUZt","http://ift.tt/1MPJYkk");
var alt1 = new Array();
var currentAd1 = 0;
var imgCt1 = 4;
function cycle1() {
if (currentAd1 == imgCt1) {
currentAd1 = 0;
}
var banner1 = document.getElementById('adBanner1');
var link1 = document.getElementById('adLink1');
banner1.src=imgs1[currentAd1]
banner1.alt=alt1[currentAd1]
document.getElementById('adLink1').href=lnks1[currentAd1]
currentAd1++;
}
window.setInterval("cycle1()",4000);
// ]]></script>
<p><a id="adLink1" target="_top"><img id="adBanner1" src="http://ift.tt/1RmlUJb" border="0" alt="" width="804" height="300" /></a></p>

Where abouts in the above will I need to include the pause functions??!