[Opserty]

You'd have to make it into a "vB Page" How to create your own vBulletin-powered page! (uses vB templates)

Or you could do this by just adding:

PHP Code:

$cwd = getcwd();
chdir('path/to/forum');
require_once('global.php');
chdir($cwd);

if(!$vbulletin->userinfo['userid'])
{
    echo 'Login | Register';
}
else
{
    echo 'Welcome '. $vbulletin->userinfo['userid'];
}