How to actively control a servo using an Arduino Uno, python, and your PC
This demo shows you how to control a servo by inputting commands into the python Idle. By itself it is pretty useless, but once you start editing the python file to control the servo/servos with different inputs it can get pretty handy. (mouse, arrow keys, etc.)
I've uploaded all the files you need for the demo here.
For more detailed written instructions you can go here.
Links for individual downloads.