TkTurf provides the user with a way to manipluate any color used in the interface via the themes file. On windows, the theme file should be named C:\tkturf.thm, on Macintosh it should be inside the hard drive icon and named tkturf.thm, and under UNIX themes should just be appended to the Xdefaults file.
Themes are no longer a supported feature as of release 2.1. The code is still there, but it is too unreliable on Windows and Mac, due to bugs in those operating systems. A substitute system has been added for K users which will load the K color themes from the ~/.kderc file.