TweetWheel
I just found TweetWheel, and its really cool. Made by Augusto Becciu.
Enter a Twitter ID (I used my ID: rtkrum), and in real time it will generate a connection wheel built from 100 people that person is following. Hover the mouse over any of the names, and it will show the connections that that person is also following on Twitter.
It takes a few minutes to load the user data.