wxPython

wxPython is a GUI toolkit for the Python programming language. It allows Python programmers to create programs with a robust, highly functional graphical user interface, simply and easily. It is implemented as a Python extension module (native code) that wraps the popular wxWidgets cross platform GUI library, which is written in C++.

Like Python and wxWidgets, wxPython is Open Source which means that it is free for anyone to use and the source code is available for anyone to look at and modify. Or anyone can contribute fixes or enhancements to the project.

wxPython is a cross-platform toolkit. This means that the same program will run on multiple platforms without modification. Currently supported platforms are 32-bit Microsoft Windows, most Unix or unix-like systems, and Macintosh OS X.

• http://www.wxpython.org/

pyQT

PyQt is a set of Python bindings for Nokia’s Qt application framework and runs on all platforms supported by Qt including Windows, MacOS/X and Linux. There are two sets of bindings: PyQt v4 supports Qt v4; and the older PyQt v3 supports Qt v3 and earlier. The bindings are implemented as a set of Python modules and contain over 300 classes and over 6,000 functions and methods.

• http://www.riverbankcomputing.co.uk/software/pyqt/download
• Supports lots of great libraries such as:
  • • The QtNetwork module contains classes for writing UDP and TCP clients and servers. It includes classes that implement FTP and HTTP clients and support DNS lookups. Network events are integrated with the event loop making it very easy to develop networked applications.
    • The QtOpenGL module contains classes that enable the use of OpenGL in rendering 3D graphics in PyQt applications.
    • The QtWebKit module implements a web browser engine based on the WebKit open source browser engine used by Apple’s Safari. It allows the methods and properties of Python objects to be published and appear as JavaScript objects to scripts embedded in HTML pages.
    • The QtScript module contains classes that enable PyQt applications to be scripted using Qt’s JavaScript interpreter.

PyGTK: GTK+ for Python

PyGTK lets you to easily create programs with a graphical user interface using the Python programming language. The underlying GTK+ library provides all kind of visual elements and utilities for it and, if needed, you can develop full featured applications for the GNOME Desktop.

PyGTK applications are truly multiplatform and they’re able to run, unmodified, on Linux, Windows, MacOS X and other platforms.

• http://www.pygtk.org/

Opinion

My personal opinion is that wxPython is best for many windows developers.  PyQt looks great and has many great libraries, Qt itself is a very fast C++ library so using it is beneficial.  PyGTK is also great but more common for *nix apps.