Code:
<!-- START Self-Updating Copyright Script -->
<script language = 'JavaScript'>
<!--
function y2k(number) { return (number < 1000) ? number + 1900 : number; }
var today = new Date();
var year = y2k(today.getYear());
document.write('JumpStationZ © '+year+' all rights reserved.');
//-->
</script>
<!-- END Self-Updating Copyright Script -->

Works like a charm for me and my site.. hehe
Might want to change the JumpStationZ part though
EDIT:
actually, all parts in yellow are optional