[link|http://www-users.kawo2.rwth-aachen.de/~razzfazz/|Two-Finger-Scrolling with pre-2005 PowerBooks and iBooks]
This is a hack to activate two-finger scrolling on supported pre-2005 PowerBooks and iBooks (i.e. those with a "W-Enhanced" trackpad, including most AlBooks and recent iBooks) on OS X 10.3.
There's a script on the page that will test your system for the W-Enhanced trackpad.