Mac only: One of OS 10.7’s interesting features is iOS-like trackpad scrolling, in which you drag your fingers down to scroll up (and vice-versa). Free app Scroll Reversal will add this feature to pre-Lion versions of OS X.
I’m personally not a fan of Lion’s “backward” scrolling, but a lot of people like it—especially those used to using iPhones and iPads all the time. If you can’t wait for Lion to come out and want the feature on your Leopard- or Snow Leopard-clad MacBook, you can use Scroll Reverser to do it. There isn’t much else to say—it’ll just sit in your menu bar and just reverse all your scrolling, and you can quit it at any time to get the old style scrolling back.
Scroll Reversal is a free download for OS X Leopard and above.