Visit www.facebook.com/settings?tab=applications to see what applications and websites you’re logging in to using your Facebook credentials.

You have 3 tabs to look at:

• Active: You recently logged into them with Facebook. These are active apps and websites that can access your Facebook data you chose to share with them.
  Use this list to: 1) View and update the info they can request and 2) Remove the apps and websites you no longer want.
• Expired: You did not log into them with Facebook for a quite a while. These are apps and websites you’ve logged into with Facebook before, so they may still have access to info you previously shared, but their ability to make additional requests for private info has expired. You can still log into these apps and websites using Facebook.
  Use this list to: 1) Renew access to apps and websites, 2) Edit the info they can request and 3) Remove the apps and websites you no longer want
• Removed: These are apps and websites you removed from your account. This means they may still have access to info you previously shared, but can’t make additional requests for private info. You cannot log into these apps and websites using Facebook without authorizing them again.
  Note: Keep in mind that app and website developers may still have access to the data you previously shared. Facebook says you should contact the app or website developers for more information.
  Use this list to view details about your removed apps and websites.

Source: www.facebook.com/help/218345114850283