in reply to Creating a Windows GUI...?
Student of all things good and Perl,
Have you looked into the freely available SpecTcl? Download this gem, read the tutorial, and hand tweak the callback function stub. Viola! You've got a great GUI. What's more it is a fine way to learn Tk programming through code inspection. I personally recommend the O'reily's Tk book, crap for learning it but it makes a good reference.
I have seen references on source forge for other GUI generators, but they are still quite beta. Give SpecTcl a whirl then pass on what you have learned! Peace to you and yours, fellow disciple.