I had to remove this line to avoid an error -- there's more info in point 5 of this blog post:

http://simonmacdonald.blogspot.com/2011/07/upgrading-your-phonegap-android.html

Author: pamelafox

Android/Facebook/www/facebook.js

@@ -43,7 +43,6 @@
      */
     PhoneGap.addConstructor(function() {
         PhoneGap.addPlugin("facebook", new Facebook());
-        PluginManager.addService("FacebookAuth", "com.hipsnip.plugins.facebook.FacebookAuth");
     });
 
 })();