Like Josh said above, you basically want to delete that entire section of code that was in your template by default and then paste the code you got from Google Analytics in its place.
So remove all of this:
<!-- GOOGLE ANALYTICS. ENTER YOUR CODE and UNCOMMENT block -->
<!--
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "YOURCODE";
urchinTracker();
</script>
and put this in its place:
<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-3839367-1']);
_gaq.push(['_setDomainName', 'enkata.com']);
_gaq.push(['_trackPageview']);
(function() {
var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
})();
</script>