Compatible with XenForo 1.1.2
You are free to edit this code as you see fit but please do not distribute it on other sites. If you have an idea for a better version, let's keep it here and share with everyone to make the XenForo community better!
Options in the Admin CP to enable or disable the button from the Share Page (footer), Sidebar or Lightbox overlay! Admin CP > Home > Options > Pinit Share Button
Many thanks to Chris Deeming for turning the template edit into an add-on for me!