The object ID is returned by the create call. There is nothing similar to the SQL method of obtaining the ID.

The return value of a query returns an array of sObjects; you do not need, nor should you try, to create new ones.

You may want to take a look at the PHP Toolkit and it's documentation here.

I believe that this will help with your immediate question: 

<?php

        // note that these path setting probably do not match yours 

        define('SOAP_CLIENT_BASEDIR', './soapclient');

$path = '/Library/WebServer/Documents/phptoolkit/soapclient';

ini_set('include_path',ini_get('include_path').':'.$path);

require_once ('SforcePartnerClient.php');

require_once ('SforceHeaderOptions.php');

require_once ('userAuth.php');

        try {

   $mySforceConnection = new SforcePartnerClient();

   $mySoapClient = $mySforceConnection->createConnection($path.'/partner.wsdl.xml');

   $mylogin = $mySforceConnection->login($USERNAME, $PASSWORD);

          $fields = array (

            'Name' => 'Bogus Records',

            'BillingCity' => 'Nashville',

            'BillingState' => 'TN',

            'Phone' => '510-555-5555');

          $sObject = new SObject();

          $sObject->fields = $fields;

          $sObject->type ='Account';

          $createResponse = $mySforceConnection->create(array($sObject));

          $AccountId = $createResponse->id;

          print_r($createResponse);

          $fields = array (

            'FirstName' => 'John',

            'LastName' => 'Smith',

            'Phone' => '510-555-5555',

            'AccountId' => $AccountId);

          $sObject2 = new SObject();

          $sObject2->fields = $fields;

          $sObject2->type = 'Contact';

          $createResponse = $mySforceConnection->create(array($sObject2));

          $ContactId = $createResponse->id;

          print_r($createResponse);

 $query = "Select c.LastName, c.Id, c.FirstName, c.Account.BillingState,

 c.Account.BillingCity, c.Account.Name, c.Account.Id 

 From Contact c

 Where c.Account.Name = 'Bogus Records'";

 $response = $mySforceConnection->query($query);

          $queryResult = new QueryResult($response);

 print_r($queryResult);

        } catch (Exception $e) {

          echo $mySforceConnection->getLastRequest();

          echo $e->faultstring;

        }

?>