JoyToKey lets you map joysticks to keyboard buttons to control programs that aren't joystick-aware. Gamepad Companion is a similar thing for Mac but it's nagware and it annoyed me. Also I wanted the ability to automatically switch configurations depending on the active application. So: Enjoy.
Somewhat related: half-working hack to get the tilt-sensor on a generic PS3 guitar hero controller to work with Frets on Fire.
