Free Forth Compilers
Win32Forth is ANS compatible, Forth language application development system with many tools - It includes an interactive console and an integrated extensible source level debugger.
Gforth is a fast and portable implementation of the ANS Forth language. It works nicely with the Emacs editor, offers some nice features such as input completion and history and a powerful locals facility.
bigFORTH is a native code Forth. It is available for Linux and Windows 95/98/NT under GPL. The most striking feature is the graphical user interface MINOS and the form editor Theseus (MINOS and Theseus are still beta).
A 32 bit MSDOS excerpt of fig-Forth
A LInux NAtive Forth
World's first Forth compiler for the .NET platform.