Create a GUI from a XML schema automatically
Go For PyQt:
http://www.riverbankcomputing.co.uk/software/pyqt/download
Download The Qt Developers tool to generate the gui automatically
www.qtsoftware.com/products/developer-tools
For schema validation try lxml
It's worth taking a look at Jaxfront which is able to consume an XSD and generate a form (including HTML). You can also supply an instance XML document for it to load into the GUI, and save out instance XML documents too.
I tried it with one of our fairly complicated XSD's and it worked pretty well.
Sadly it's written in Java - I'm still looking for something which can generate .NET web forms or XAML/WPF! In fact even XFORMS would be good.