how to login to another site via PHP

I wanted to find out how to login to another site via PHP… I don’t know the proper term for it, but basically, I want a user to be able to enter their login information for another website on mine, and interact with it through mine.Is there any tutorial?
thanks

Answer

There are few ways to do the job (actually, you just need to send POST data to the other site).

You can use :

• curl (example: http://davidwalsh.name/execute-http-post-php-curl),

• stream context (example: http://php.net/manual/en/function.stream-context-create.php),

• or directly with sockets (example: http://www.jonasjohn.de/snippets/php/post-request.htm).