gnuTaxes is an Open Source GNOME tax preparation application.
Open Tax Solver
OpenTaxSolver (OTS) is a free program for calculating Tax Form entries and tax-owed or refund-due, such as Federal or State personal income taxes. An optional graphical front-end, OTS_GUI, was recently added. Currently, TaxSolver versions are available for 2004 tax year: US 1040 and Schedules A, B, C, & D; States: California, Pennsylvania, New Jersey, North Carolina, New York, Massachussets, Ohio, Virginia, and Canada.
OpenTaxFormFiller programmatically fills U.S. tax forms from JSON data.
Used by individuals and professional tax preparers. It is written in Perl using Tk, and incorporates the PDF::Create module for printing files in the PDF format.
PTax98 is a Perl script using the Tk.pm module. It computes the federal tax form 1040EZ for tax year 1998.
SequelBasis is a free (GPL-licensed) cost basis and capital gain calculator for mutual funds. Cost Basis and capital gain are calculated using both the FIFO and Average Cost Basis Single Category methods. Entering mutual fund data and generating comprehensive reports is simple.
Taxbird is a GNOME based graphical user interface to gather, encrypt, and send (using libgeier) tax declarations to the German inland revenue offices. It's the first free replacement for the proprietary application "ElsterFormular" maintained by the inland revenue offices.