One nice WYSIWYG i've played with is QtDesigner, which can be configured with a plugin to use PerlQt bindings instead of C++ . take a look at this screenshot. The project page is here. It's similar to visual basic, in it's interface. I prefer Qt's clever SIGNAL()/SLOT() event model to toolkits that use callbacks.

I believe PerlQt only works on UNIX platforms, and under Cygwin.