How to Create new Customer in magento or update customer info in magento

$customer = Mage::getModel('customer/customer');

$password = '123456';

$email = 'sanjay@rao.com';

$customer->setWebsiteId(Mage::app()->getWebsite()->getId());

$customer->loadByEmail($email);

if(!$customer->getId()) {

    $customer->setEmail($email);

    $customer->setFirstname('Sanjay');

    $customer->setLastname('Rao');

    $customer->setPassword($password);

}

try {

    $customer->save();

    $customer->setConfirmation(null);

    $customer->save();

    //Make a "login" of new customer

    Mage::getSingleton('customer/session')->loginById($customer->getId());

}

catch (Exception $ex) {

    Zend_Debug::dump($ex->getMessage());

}