Official homepage:

What: KiwiTcl
Description: Free (as in freedom) binary distribution of Tcl/Tk for Microsoft Windows and SCO UnixWare, can be used in production systems freely, as opposed to ActiveTcl.
Updated: 07/2013
Contact: See web site

(RJH: Link appears dead at 2nd Jan 2018. I have a copy of kiwitcl_8.6.0_x86_msvc10.exe - approx. 4.5MB, is there any community repository where I could leave it...?)