Chris Zurbrigg, creator of the absolutely fantastic Blue Pencil Sketchpad for Maya, has posted an introduction to creating dialogs in Maya by way of PyQT.

In the first part of this video tutorial users will learn how to create a new QDialog, set the layout and add the required widgets

Chris notes that this is an intermediate level stuff, basically for people who are familiar with Python, but may be new to PyQT and using PyQT for Maya.