Apple has introduced a new feature in OS X Lion, which is known to be ‘natural’ scrolling. Previously, you would have moved your finger down to move down and up on your mouse/trackpad, whereas in new ‘natural’ scrolling, the process is reversed.
The new feature seems to be difficult for some users. The new feature can be disabled in the settings to use the previous scrolling.
Go to System Preference > Mouse > then remove the tick from “Scroll direction: natural” or “Move content in the direction of finger movement when scrolling or navigating”
Now the scrolling will be in reverse.
