ぱんぴーまっしぐら

まさに誰得。
ブラウザベースは情報いっぱいあったんだけど、クライアントベースが見つからなかったので。
取得したaccess_token、access_token_secretを利用の仕方は下記で。
PEAR::HTTP_OAuthでxAuth – ぱんぴーまっしぐら

#!/usr/bin/env php
<?php
require_once 'HTTP/OAuth/Consumer.php';

define('CONSUMER_KEY',    'xxxxxxxxxxxxxxxxxxxx');
define('CONSUMER_SECRET', 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx');

try {

  $http_request = new HTTP_Request2();
  $http_request->setConfig('ssl_verify_peer', false);

  $consumer_request = new HTTP_OAuth_Consumer_Request();
  $consumer_request->accept($http_request);

  $consumer = new HTTP_OAuth_Consumer(CONSUMER_KEY, CONSUMER_SECRET);
  $consumer->accept($consumer_request);

  $consumer->getRequestToken('http://twitter.com/oauth/request_token');
  $url = $consumer->getAuthorizeUrl('http://twitter.com/oauth/authorize');

  if (!$stdin = fopen('php://stdin', 'r')) {
    throw new Exception('stdin open failed');
  }

  echo 'Visit the following URL in your browser to authenticate twitter: ';
  echo $url."\n";
  echo 'Enter Twitter OAuth PIN: ';
  $pin = trim(fgets($stdin, 64));
  $consumer->getAccessToken('http://twitter.com/oauth/access_token', $pin);

  echo 'access_token: '.$consumer->getToken()."\n";
  echo 'access_token_secret: '.$consumer->getTokenSecret()."\n";

} catch (Exception $e) {

  echo $e->getMessage().' in '.$e->getFile().' line '.$e->getLine()."\n";
  exit(1);

}