Scroll Reverser for Mac - On Demand Scroll Control for Lion
http://www.macupdate.com/app/mac/37872/scroll-reverser
I'm getting fairly used to the new direction of the trackpad scroll in Lion and it's starting to feel very natural, especially given the other gestures. The problem is that I sometimes use my laptop on a KVM switch and jump back and forth between it and Windows or Ubuntu. Enter the tiny app, Scroll Reverser from PilotMoon Software.
This free app is a nice solution for me since it allows me to set the USB mouse to still use the scroll wheel in the same direction on OS X as on the other two platforms without messing with the trackpad settings. It only applies this while it's running so there's no need to mess with your system settings. Just run it when you need it and quit when you're done.
The other good use case I can see for this would be when someone else needs to use your machine for a minute or two (presentations, browsing, pair programming, etc.) and you'd like to let them use the trackpad or mouse the way they're used to doing it. Just fire up Scroll Reverser while they use your machine and then quit it when they're done.
