This is a script-fu of the process as described by gimpforphotos.com at: gimpforphotos.com two strip technicolor
I didn't create the process, I just wrote the script that does everything described in the tutorial!
More info on the process here: http://en.wikipedia.org/wiki/Technicolor#Two-color_Technicolor
When installed, this should show up under
Colors → Two-strip Technicolor...
Apparently I can't figure out how to upload files... :) Sorry about that all - fixed with a script.
This was done mostly as a quick exercise for myself (but it does follow the process on the gimpforphotos.com page exactly).