Notice: There is a newer version of this app, which also works with groups, please check it out at http://dtinth.github.com/friendlist/
This is a tool for you if you have most of your friends already organized nicely in lists. But then you added several more friends and didn't put them in any lists. You, like me, couldn't find all the friends that you haven't put in any lists in Facebook's user interface. This tool helps you find them and helps you put them in the right list. This tool can also suggest the list that most of your and their mutual friends are in. On your left is the filter view. You can view all friends, friends inside a list, or friends not in any lists. Then below this text, you see the friends that matches the criteria. On the right, you can click to add or remove the selected friend to/from the list.