This may or may not be new, but I just stumbled upon it. If you are on a web page that requires scrolling to see the whole page, you can press and hold the mouse wheel button (assuming you have a mouse with a mouse wheel button), and a little icon will appear in the center of the screen with up and down arrows (as seen at right).
Now you can move the page up and down (or side to side) simply by moving the mouse itself instead of the mouse wheel.
[robg adds: This will only work if you don't have your center button programmed to do something else in your mouse's software.]

