title: Best way to way a php script that logs a user in when they click a link on another website?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/6567088/single-sign-on-how-to-implement">Single Sign On - how to implement?</a>  </p>
  </blockquote>
  
  
  
  <p>I have a two website which are totally unrelated. I need to write a php script that will send a user to the second site and log them in. Need to do this securely and also send over the user information (like username, profile details etc).</p>
  
  <p>What is the best way to achieve this?</p>