Sample Call

<?php
// SOAP_CLIENT_BASEDIR - folder that contains the PHP Toolkit and your WSDL
// $USERNAME - variable that contains your Salesforce.com username (must be in the form of an email)
// $PASSWORD - variable that contains your Salesforce.com password

define("SOAP_CLIENT_BASEDIR", "../../soapclient");
require_once (SOAP_CLIENT_BASEDIR.'/SforceEnterpriseClient.php');
require_once ('../userAuth.php');

try {
  $mySforceConnection = new SforceEnterpriseClient();
  $mySoapClient = $mySforceConnection->createConnection(SOAP_CLIENT_BASEDIR.'/enterprise.wsdl.xml');
  $mylogin = $mySforceConnection->login($USERNAME, $PASSWORD);

/*--------------------------------------------------------\
| Please manage the values for OBJECT ID from file 
| userAuth.php
\--------------------------------------------------------*/

  $sObject1 = new stdclass();
  $sObject1->Id = $UPDATEOBJECTID1;
  $sObject1->FirstName = 'testupdate';
  $sObject1->City = 'testupdateCity';
  $sObject1->Country = 'US';

  $sObject2 = new stdclass();
  $sObject2->Id = $UPDATEOBJECTID2;
  $sObject2->FirstName = 'testupdate';
  $sObject2->City = 'testupdate';
  $sObject2->State = 'testupdate';
  $sObject2->Country = 'US';
  $sObject2->fieldsToNull = array('Fax', 'Email');

  $response = $mySforceConnection->update(array ($sObject1, $sObject2), 'Lead');

  print_r($response);

} catch (Exception $e) {
  print_r($mySforceConnection->getLastRequest());
  echo $e->faultstring;
}
?>

Sample Output

Array
(
    [0] => stdClass Object
        (
            [id] => 00Q5000000VbFmREAV
            [success] => 1
        )

    [1] => stdClass Object
        (
            [id] => 00Q5000000VbFgTEAV
            [success] => 1
        )

)