Update!
Sorry, i have found a updated version of this. Here: http://bavotasan.com/2011/a-better-voting-system-for-wordpress/
The functions file looks like this:
add_action("wp_ajax_add_votes_options", "add_votes_options");
add_action("wp_ajax_nopriv_add_votes_options", "add_votes_options");
function add_votes_options() {
if (!wp_verify_nonce($_POST['nonce'], 'voting_nonce'))
return;
$postid = $_POST['postid'];
$ip = $_POST['ip'];
$voter_ips = get_post_meta($postid, "voter_ips", true);
if(!empty($voter_ips) && in_array($ip, $voter_ips)) {
echo "null";
die(0);
} else {
$voter_ips[] = $ip;
update_post_meta($postid, "voter_ips", $voter_ips);
}
$current_votes = get_post_meta($postid, "votes", true);
$new_votes = intval($current_votes) + 1;
update_post_meta($postid, "votes", $new_votes);
$return = $new_votes>1 ? $new_votes." votes" : $new_votes." vote";
echo $return;
die(0);
}
Perhaps i just need a bit of code to refresh the $votes count?