Converting this to vB authentication

[Andem]

Hey. Posted recently in the jobs forum but no avail. Maybe someone here can help? You all seem like friendly people

Here's what I'm trying to do:

PHP Code:

function chk_admin_login()
{
        global $config;
        if($_SESSION['AUID']!=$config['admin_name'] || $_SESSION['APASSWORD']!=$config['admin_pass'])
        {
                header("Location:$config[baseurl]/siteadmin/login.php");
                exit;
        }
}

//CHECK MEMBER LOGIN
function chk_member_login($viewkey="")
{
        global $config,$conn;

        $sql="select * from signup where UID=$_SESSION[UID]";
        $rs=$conn->execute($sql);
        if($_SESSION['UID']=="" || $_SESSION['EMAIL']=="" || $rs->recordcount()==0)
        {
                $q = "";
                while(list($k,$v)=each($_GET)){$q.="&$k=$v";}
                $q=base64_encode($q);
                if($q!="")$add="&add=$q";
                $temp=$_SERVER['PHP_SELF'];
                $path=explode("/",$temp);
                $page=$path[count($path)-1];
                $page=str_replace(".php","",$page);
                header("Location:$config[baseurl]/signup.php?next=$page$add");
                exit;
        }
}

function session_to_db()
{
        global $conn;
        $sql="select * from signup where UID=$_SESSION[UID]";
        $rs=$conn->execute($sql);
        if($rs->recordcount()>0)
        {
                $_SESSION[EMAILVERIFIED]=$rs->fields['emailverified'];
        }
} 


Getting rid of the above and instead using vBulletin authentication system instead. I'm new to the software, and have too much experience with the phpbb code.. so no idea of where to go from here!

Instead of using the database for this script, I could easly use select * from db_vbulletin.signup instead of just signup easily instead.