From today’s mail bag:
In Lion, the mouse scrolling feature now works “upside down” or in reverse of how it responded under Snow Leopard. How do I change this behavior?
Mouse settings are managed by the Mouse pane located in System Preferences. Access System Preferences from the Dock or from the Apple Menu located in the upper left corner of the screen.
Look for a check box at the top of the Mouse preferences that’s labeled, “When using gestures to scroll or navigate, move content in the direction of finger movement.” Uncheck this box, then close out of System Preferences.