Smart Scroll offers smooth and easy iPhone-like scrolling:

* Super Scroll makes your scroll wheel smoother, faster and more
comfortable. And it lets you reverse scrolling on the Mac to match your
iPhone. Try it!

* Grab Scroll gives you a Hand tool to easily move (and “throw”!) any
window’s contents.

Other features include Universal Scroll Keys that let you scroll from the
keyboard, FileMaker Pro and AppleWorks enhancements, and more.

Smart Scroll is shareware ($19 single user license) and runs on Mac OS X
10.3.9 or newer (PPC/Intel).
More info: (http://www.marcmoini.com/sx_en.html)
Download:
10.5 & 10.4:
(http://www.marcmoini.com/SmartScrollX_2.7.5b2_Leopard.dmg)
10.3: (http://www.marcmoini.com/SmartScrollX_2.7.3.dmg)

Version 2.7.5 – February 25, 2008
* Full support for Mac OS X 10.5.2 Leopard
* New name, now simply Smart Scroll (was Smart Scroll X).
And Super Wheel is now Super Scroll.
* For Mac OS X 10.3 Panther, please use Smart Scroll 2.7.3