What authentication system for my... web apps?

[eluser]jbrozz[/eluser]
this is a first step

class CI_Auth {

function auth($username, $password, $table = 'users', $remember = null)
{
$sql = "SELECT id, username, password FROM ".$table."
WHERE username='".trim($username)."'
AND password='".trim($password)."' LIMIT 1";

$res = $this->db->query($sql);

if($res == true) return true;
else return false;
}

}

post in /system/library/