Quick-Tk ,by Ian Kjos ,is a relatively complete graphical Tk development environment. Features cut/copy/paste, jump from function to function, immediate mode Tk with history, widget wizards, and preview of generated widgets. Has project management, creating a project from a Tcl/Tk file (if you have awk in your path). Requires Tk 4.1 or newer. License is GPL. Currently at version 0.5.
SEH 2004-11-29: Started right up on Windows. Played with it a bit, looks intriguing!