Ehh.. yadda yadda yadda poll.. yadda yadda yadda cookie.. Hmm...
I'm sorry I don't quite understand your problem.
Correct me if I'm wrong, but you want to show a list of polls but exclude the ones the visitor already voted to ?
I'd say set a cookie if the poll is used:
$array_cookie[$poll_id] = setcookie();
And when displaying the list of available polls:
if ( !$array_cookie[$poll_id] ) {
[this cookie is not set]
} else {
[this cookie is set]
}
$poll_id is the id from the database row containing poll information. So you step through your available polls with while (and mysql_fetch_array).