Don’t know if you’ve already found it… I mention it anyway for future surfers…
I was looking for the same, and found this piece of code :
<script type="text/javascript">
function trackConv(google_conversion_id, google_conversion_label) {
var image = new Image(1, 1);
image.src = "//www.googleadservices.com/pagead/conversion/" + google_conversion_id + "/?label=" + google_conversion_label + "&script=0";
}
</script>
Then for links which you want to track just do this :
<a onclick="trackConv(1234567890, 'LQV8CNq6RxCKlPbvAw');" href="http://www.example.com">Link</a>