sessions

I need some help with sessions. I read the sections in the manual and searched for tutorials, but I still can't get a straight forward example of how sessions work. I need to pass variables to a page that will load in a new browser window. I used session_register, but when I look in the $HTTP_SESSION_VARS, it doesn't exist. I tried using start_session and still no luck. Once I get the session vars registered, how do I access them. I am able to pass the session id as a var, I'm going it like page.php?sid=$<sid_var>. Is there a better way, do I need to do this at all? I'm confused as hell and can't find a working example anywhere. Help! - Anthony