I've solved it Justin....
OK I now see what you mean after I vote and results are displayed....the poller jumps to the top of page & cropping (rest of page jumps up with it, hiding everything above poller under the header. This is also happening using IE6 also
I'm embarrassed I didn't spot this sooner.....ah well
You are correct to assume it is the onclick <a href="#" onclick="castMyVote.....the "#" causes this to happen in IE but not FF.
Replace the "#" with the actual URL of your iframe source....so for example, in my case the line to change in the ajax-poller.php will read something like this.....
onclick="castMyVote(<?php echo $pollerId; ?>,document.forms)"><img src="images/vote_button.gif"></a>
Give this a try and it should keep your poller stationary stopping it jumping up the page