mailchimp provide a PHP wrapper at https://bitbucket.org/mailchimp/mailchimp-api-php which tends to make life a million times easier.
The problem what seems to be happening here is that you are doing a GET rather than a POST
try
$apikey = '**********-us3';
$listID = '******';
$email = "**************";
$fields = array('apikey' => urlencode($apikey), 'id' => urlencode($listID), 'email_address' => urlencode($email), 'output' => 'json' );
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');
$url = 'https://us2.api.mailchimp.com/2.0/lists/subscribe';
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
$data = curl_exec($ch);
$arr = json_decode($data, true);
curl_close($ch);
if ($arr == 1) {
echo 'Check now your e-mail and confirm your subsciption.';
} else {
echo $arr['code'];
switch ($arr['code']) {
case 214:
echo 'You are already subscribed.';
break;
// check the MailChimp API for more options
default:
echo 'Unkown error...';
break;
}
}
And let me know if that helped. If not I can see if I can try and set something up myself so I can test some code.