How to setup the oauth module?
You can try the Drupal Services, REST Server and 3-legged OAuth tutorial here. Just be pay intention in this part :

$oauth-&gt;fetch("$api_url/node/1");


This is just for creating the GET request. If you want to create the POST request. It should be something like.

 $oauth-&gt;fetch("$api_url/user/vote.json",array('nid'=&gt;10),OAUTH_HTTP_METHOD_POST);