Is there a way to have Snow Leopard match the scrolling behavior of Lion?
This post by John Gruber outlines several possibilities:

For OSX:


Scrollvetica
Scroll Reverser


For Windows:


An AutoHotkey hack


On the Mac side, Scroll Reverser looks nice in the menu bar, is free, and works from Tiger to Snow Leopard (10.4 - 10.6).