Editor: xGestures is a shareware program for Mac OS X 10.3 and later that allows you to use mouse gestures in all aspects of your Macintosh computer. You can define gestures for individual programs, or for the whole computer, and map them to useful functions like closing or minimizing windows, switching or launching applications, picking menu items or performing keystrokes, triggering Exposé, and much more!
It gives you a lot of control over how your computer will manage mouse gestures. You can specify global gestures that will apply to all applications, but you can also specify that certain applications shouldn't use global gestures. Also, if there's a program that you don't want gestures enabled in, possibly because you need to use your mouse and all of its buttons normally, you can disable gestures in that application and it will continue to function normally. Better still, you can enable gestures in a program without changing the functionality of any of the mouse buttons, allowing xGestures mouse gestures to be available in a program that already has its own mouse gestures, like Opera or Mozilla!
If you have a mouse with multiple buttons, you can specify that the third or fourth button be used to perform gestures if you want the right mouse button's functionality to remain the same. Also, you can specify a combination of modifier keys that need to be pressed in order for a gesture to happen, so that it's possible to perform mouse gestures even with a one button mouse.
I wrote xGestures because, before I had a Macintosh, I became hooked using mouse gestures in the Opera web browser, and then later using the program StrokeIt, which gave mouse gestures functionality to all aspects of Windows. Though there is already a mouse gestures for OS X, called Cocoa Gestures, I was unsatisfied with it, because it only allowed me to use gestures in Cocoa Applications (and not the Finder), and also was very limited in what functions it could have the gestures perform.