Stuck with Prototype. Here's a jsfiddle, but you'll have to use the DRAFT feature () to see it in IE8. http://jsfiddle.net/trevordixon/7rxaE/
<image id="spinner" src="http://cdn3.iconfinder.com/data/icons/transfers/100/239327-loading_spinner-32.png">
<script>
var angle = 0;
setInterval(function() {
angle += 0.1;
$('spinner').setStyle({
'-ms-filter': '"progid:DXImageTransform.Microsoft.Matrix(' +
'SizingMethod = \'auto expand\', ' +
'M11 = ' + Math.cos(angle) + ', ' +
'M12 = ' + -Math.sin(angle) + ', ' +
'M21 = ' + Math.sin(angle) + ', ' +
'M22 = ' + Math.cos(angle) + ')"'
});
}, 16);
</script>
I'm open to better ideas for the spinner; animated gif won't work for me for a number of reasons.