The programming style imposed by PyQt (and other GUI toolkit wrappers) is to create an application instance with some widgets and to enter into an event loop that locks you from the Python command line interpreter.
Module iqt enables you to:
Module iqt works by hooking qApp->processEvents() on the event hook of the readline module. The GNU readline library closes the event loop by calling qApp->processEvent() at a maximum rate of 10 times per second while reading your keyboard input.
To see how iqt works, play with ICompass.py by running
python -i ICompass.py