To use curl you have to make sure curl is enabled.  If you are unsure you can either just test it or make a file with the following code to verify.{codecitation}
phpinfo();
{/codecitation}
Make sure to delete this test file after for security purposes.  If curl is not enabled you'll need to modify your php.ini file and uncomment this line by removing the semi colon.  Then you'll need to restart your webservice.{codecitation class='brush:text'}
;extension=php_curl.dll
{/codecitation}

Here is a simple curl example {codecitation}
$ch = curl_init ('http://neta1o.com/ref.php');
curl_setopt ($ch,CURLOPT_REFERER,'http://google.com');
curl_setopt ($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)');
curl_setopt ($ch, CURLOPT_POST, true);
curl_setopt ($ch, CURLOPT_POSTFIELDS, 'name=neta1o&type=admin');
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
$returndata = curl_exec ($ch);
echo $returndata;
{/codecitation}
Note:  The above form does a post with the name field set to neta1o, and the type as admin.  You could add other fields as well.