[Adrian Schneider]

PHP Code:

// Note the ID at the end
if ($vbulletin->userinfo['usergroupid'] == 6)
{
    echo "You're an administrator, eh!";
}
else
{
    echo "Be gone, low level scum.";
} 


If you want to check secondary groups (or multiple, with ease):

PHP Code:

if (is_member_of($vbulletin->userinfo, 6, 7, 8))
{
    echo "You're either a secondary or primary member of the groups 6 7 or 8.";
} 


Using is_member_of allows to add as many groups as you'd like (somewhat new functionality)...