Friends Invitation Plugin - Hosted or PHP
<p>I'm wondering if there's a good "hosted" solution for managing friend invites (ala LinkedIn) I know of AddThis, but unless I'm mistaken that looks geared towards sharing specific articles/content.  </p>

<p>I'm looking for something that could be integrated neatly into the sign up process, with minimal added coding effort.  Just need simple grab contacts from Gmail, FB, Hotmail, etc.</p>

<p>Perhaps the best way to go is a PHP plugin.  Can anyone recommend the best one out there? Free would be best.</p>
