Smart Scroll X has been updated by the author to version 2.5 on Friday. The new version has finer speed control and a greater speed range.
Version 2.5 also includes a scroll wheel accelerator for extra-fast scrolling as well as Grab Scroll, which "can now share a button with a 2nd action: opening links in a new tab, or any action that does not involve dragging -- not Dashboard or Expos?," according to the author.
Smart Scroll 2.5
Smart Scroll X features a "coasting" mode, just like the iPhone, and uses the momentum of the moving page to move through documents faster and with less effort. FileMaker Pro 6,7 and AppleWorks 6 are now supported.
Smart Scroll X 2.5 is a Universal Binary and requires Mac OS X 10.3.9 or later. It is priced at US$19.00.