OpenTaxSolver (OTS) is a free program for calculating Tax Form
entries and tax-owed or refund-due, such as US Federal or State
personal income taxes. An optional graphical front-end, OTS_GUI,
has been added. Preliminary versions for Canada and the United
Kingdom were posted in previous years and may be updated with help
from volunteers.

Motivations include:

    * To make tax preparation software available for all platforms.
    * To provide insight into how our taxes are calculated in clear
      unambiguous equations/code.
    * To avoid invasive, bloated commercial software packages.
    * To avoid rewriting our own individual programs each year by
      combining efforts.
    * To provide a simple reliable tax-package requiring only
      rudimentary knowledge to maintain.

WWW: http://opentaxsolver.sourceforge.net/