function tweet($message, $username, $password)
{
    $context = stream_context_create(array( 
        'http' => array( 
        'method' => 'POST', 
        'header' => sprintf("Authorization: Basic %s\r\n", base64_encode($username.':'.$password)). 
            "Content-type: application/x-www-form-urlencoded\r\n", 
        'content' => http_build_query(array('status' => $message)), 
        'timeout' => 5, 
        ), 
    )); 
    $ret = file_get_contents('http://twitter.com/statuses/update.xml', false, $context); 
 
    return false !== $ret;
}