Where:
The TclFltk package is a dynamic extension to the Tcl/Tk application development environment that delivers a GUI experience based on the FLTK (Fast Light Tool Kit) portable GUI package.
The interface is similar to the usual Tk interface but provides a widget set that has a look and feel that is platform independent. The package iteself is available from the sourceforge repository and includes an extensive amount of documentation with code examples.
The package is avalable for both Windows and Linux environments. A port to OpenMoko is also in the repository.
... it turns out this project already has two wiki pages: Tcl Fltk and Fltk Tcl Binding