Supported models include most aluminum PowerBooks introduced from 2003 to 2004 as well as all G4 iBooks.
Note: Models that have two-finger scrolling already built-in are not supported! These use a completely different, USB-based trackpad, the driver of which is not available as open source.
iScroll2 is based on Apple's AppleADBMouse-209.0.10 driver for the ADB-based trackpads found on older models, which is available as part of the publicly released Darwin source code (and covered by the APSL). The code added for supporting two-finger scrolling was written from scratch.