I would like to have some feedback about the app I developed with a friend of mine using the Gephi Toolkit. It allows you to see a clustered view of your friends and discover very interesting patterns.
It is an html5 + javascript app so that you should be able to use it from almost any device; it just requires a facebook account, don't worry, I'm really against spammy applications, it just accesses your friend list to draw the graph.
It's just a little slow if you have many friends, but it will work anyway.
Please share it if you like it

http://apps.facebook.com/friendsgraph