Sessions ???

Hi All I have a ? about setting a session. I have a functions.inc file and at the top have put my session statment that looks like this. <? session_start(); session_register("$topidID"); ?> $topicID comes from my mysql db. What i am trying to do is set the $topicID of my message board so that when a sucessful post has been made the visitor can click on a link that show the right board by topicID. so the link will look like this... http://localhost/forums/view.php?topicID=3 I am banging away trying to make this work.... Any help in the meantime is as always appreciated Thank You In Advance dave C