FoxyCart has some amazing built-in Google Analytics functionality. It's a little tricky to set up, though. Follow their guide here: http://wiki.foxycart.com/integration/googleanalytics_async to set it up.

After you do the ecommerce and goal setup on analytics, you need to add some code to your site and the FoxyCart template files. Here's the code you need.

NOTE: YOU MUST CHANGE THE XXXXXXXX-X IN ALL LOCATIONS TO YOUR UA CODE!


-----------------------------------
FOOTER.PHP CODE
-----------------------------------

<script type="text/javascript">

  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-XXXXXXXX-X']);
  _gaq.push(['_setDomainName', 'none']);
  _gaq.push(['_setAllowLinker', true]);
  _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>

<script type="text/javascript" charset="utf-8">
	fcc.events.cart.preprocess.add(function(e, arr) {
		if (arr['cart'] == 'checkout' || arr['cart'] == 'updateinfo' || arr['output'] == 'json') {
			return true;
		}
		if (arr['cart'] == 'checkout_paypal_express') {
			_gaq.push(['_trackPageview', '/paypal_checkout']);
			return true;
		}
		_gaq.push(['_trackPageview', '/cart']);
		return true;
	});
	fcc.events.cart.process.add_pre(function(e, arr) {
		var pageTracker = _gat._getTrackerByName();
		jQuery.getJSON('https://' + storedomain + '/cart?' + fcc.session_get() + '&h:ga=' + escape(pageTracker._getLinkerUrl('', true)) + '&output=json&callback=?', function(data){});
		return true;
	});
</script>








-----------------------------------
CART TEMPLATE CODE
-----------------------------------

<script type="text/javascript" charset="utf-8">
	if (window.location.hash.search(/utma/) == -1 && typeof(fc_json.custom_fields['ga']) != "undefined") {
		if (fc_json.custom_fields['ga'].length > 0) {
			window.location.hash = fc_json.custom_fields['ga'];
		}
	}
	if (typeof(fc_json.custom_fields['ga']) != "undefined") {
		$('a.fc_link_nav').each(function(){
			var href_link = $(this).attr('href') + fc_json.custom_fields['ga'];
			$(this).attr('href', href_link);
		});
	}
</script>

<script type="text/javascript">

  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-XXXXXXXX-X']);
  _gaq.push(['_setDomainName', 'none']);
  _gaq.push(['_setAllowLinker', true]);

  (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>

<script type="text/javascript" charset="utf-8">
	jQuery(function($){
		$('a.fc_cart_checkout_paypal').click(function(e){
			e.preventDefault();
			_gaq.push(['_trackPageview', '/paypal_checkout']);
			setTimeout('document.location = "' + this.href + '";', 200);
		});
	});
</script>



-----------------------------------
CHECKOUT TEMPLATE CODE
-----------------------------------

<script type="text/javascript" charset="utf-8">
	if (window.location.hash.search(/utma/) == -1 && typeof(fc_json.custom_fields['ga']) != "undefined") {
		if (fc_json.custom_fields['ga'].length > 0) {
			window.location.hash = fc_json.custom_fields['ga'];
		}
	}
</script>

<script type="text/javascript">

  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-XXXXXXXX-X']);
  _gaq.push(['_setDomainName', 'none']);
  _gaq.push(['_setAllowLinker', true]);
  _gaq.push(['_setAllowAnchor', true]);
  _gaq.push(['_trackPageview', '/checkout']);
  
  (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>

<script type="text/javascript" charset="utf-8">
	function ga_tracker() {
		if (typeof(fc_json.custom_fields['ga']) != "undefined" && jQuery('#fc_payment_method_paypal').attr("checked") == true) {
			_gaq.push(['_trackPageview', '/paypal_payment']);
			setTimeout('return true;', 250);
		}
	}
	FC.checkout.overload('validateAndSubmit', 'ga_tracker', null);
</script>





-----------------------------------
RECEIPT PAGE TEMPLATE CODE
-----------------------------------

<script type="text/javascript" charset="utf-8">
	if (window.location.hash.search(/utma/) == -1 && typeof(fc_json.custom_fields['ga']) != "undefined") {
		if (fc_json.custom_fields['ga'].length > 0) {
			window.location.hash = fc_json.custom_fields['ga'];
		}
	}
</script>

<script type="text/javascript">

  var _gaq = _gaq || [];
  _gaq.push(['_setAccount', 'UA-XXXXXXXX-X']);
  _gaq.push(['_setDomainName', 'none']);
  _gaq.push(['_setAllowLinker', true]);
  _gaq.push(['_setAllowAnchor', true]);
  _gaq.push(['_trackPageview', '/receipt']);
  
  (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>

^^receipt_only_begin^^
^^analytics_google_ga_async^^
^^receipt_only_end^^