It's an alternate trackpad driver, allowing you to turn areas of the trackpad into scrolling selector thingies, and set the corners of your trackpad to alternate keypresses.
Right now, the top-left corner of my trackpad is the right-click/ctrl-click, and the right side of the trackpad is a scrollwheel. Whee~
(try it, it's cool.)
http://www.ragingmenace.com/software/sidetrack/index.html
