sample.php

<?php
//検索キーワード
$keyword = 'アプリ';

$uri = 'http://ax.search.itunes.apple.com/WebObjects/MZSearch.woa/wa/search?term=' . urlencode($keyword) . '&media=software';
$context = stream_context_create(array('http' => array(
	'method' => 'GET',
	'header' =>
		'User-Agent: iTunes-iPhone/4.2.1 (2; 8GB)' . "\r\n"
		. 'X-Apple-Store-Front: 143462-9,2' . "\r\n"
	,
)));
$data = file_get_contents($uri, false, $context);
echo $data;