Apple reversed scrolling in OS X Lion and called the feature "natural scrolling." Not everyone liked the change, but it could. There are some people that do like the new scrolling direction and even Google has added reverse scrolling to Chrome OS. If you're a Windows user and would like to try out reverse scrolling, here's how:
Step 1: Install AutoHotkey on your Windows PC.
Step 2: Launch AutoHotkey, and when prompted to create a sample script, click the Yes button.
Step 3: When the sample script appears in Notepad, paste the following code just below the two sample hotkeys:
Step 4: Save the script in Notepad (Ctrl+S).
Step 5: Right-click on the AutoHotkey icon from the taskbar and select Reload This Script.
That's it. Now scrolling on your Windows touch pad or mouse will be reversed. To enable the script on reboot, just copy the AutoHotkey shortcut to your Startup folder. If you end up using AutoHotkey for other scripts, just copy the shortcuts to the scripts themselves into the Startup folder. To disable reverse scrolling, edit the code out of the script or uninstall AutoHotkey entirely.
(Via How-To Geek)