example:
$curl_conn = curl_init ( "http://twitter.com/statuses/update.xml" );
curl_setopt($curl_conn, CURLOPT_HTTPAUTH, CURLAUTH_BASIC );
curl_setopt ($curl_conn, CURLOPT_HTTPHEADER, array ( "Expect:" ) );
curl_setopt($curl_conn, CURLOPT_USERPWD, $user . ":" . $password );
curl_setopt($curl_conn, CURLOPT_POST, true );
curl_setopt($curl_conn, CURLOPT_RETURNTRANSFER, 1 );
curl_setopt ( $curl_conn, CURLOPT_POSTFIELDS, array ( "status" => $msg ) );
$response = curl_exec ( $curl_conn );