An example of using my OpenID library with CodeIgniter (http://github.com/kbjr/EasyOpenID)

gistfile1.php

<?php

//...

function try_auth()
{
    // load the library
    $this->load->library('EasyOpenID');

    // start the request
    $this->easyopenid
        ->provider('google')
        ->return_to('Yours/finish_auth')
        ->required(array( 'email', 'name' ))
        ->make_request();
}

function finish_auth()
{
    // load the library
    $this->load->library('EasyOpenID');

    // get the returned user data
    $user_data = $this->easyopenid->fetch_result();

    // continue processing ...
}

//...