There are a few GUI (Graphical User interface) builders available for
Tk.

XF is the oldest major GUI builder app for Tcl/Tk and is available at
http://www.cimetrix.com/sven/xf.html.

Visual Tcl (not the SCO version of Tcl) is a new GUI builder with some
IDE features for Tcl/Tk and is available at
http://www.neuron.com/stewart/vtcl/.