Twitter is very popular since some time now, and you probably already have an account there. What about using cURL to tweet from your server without connectiong to Twitter?
<?phpweb
// Set username and password
$username = 'username';
$password = 'password';
// The message you want to send
$message = 'is twittering from php using curl';
// The twitter API address
$url = 'http://twitter.com/statuses/update.xml';
// Alternative JSON version
// $url = 'http://twitter.com/statuses/update.json';
// Set up and execute the curl process
$curl_handle = curl_init();
curl_setopt($curl_handle, CURLOPT_URL, "$url");
curl_setopt($curl_handle, CURLOPT_CONNECTTIMEOUT, 2);
curl_setopt($curl_handle, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl_handle, CURLOPT_POST, 1);
curl_setopt($curl_handle, CURLOPT_POSTFIELDS, "status=$message");
curl_setopt($curl_handle, CURLOPT_USERPWD, "$username:$password");
$buffer = curl_exec($curl_handle);
curl_close($curl_handle);
// check for success or failure
if (empty($buffer)) {
echo 'message';
} else {
echo 'success';
}
?>