Packaging your software for installation is a difficult, nasty, unpleasant, arduous, error-prone task. It is awfully enticing to just give up, zip up your Python source code together with a README file, and leave it at that.
In some cases, doing just that might be wise: if your intended users are technically knowledgeable, you can ask them to install Python, edit system variables, and mess around until everything works. Typically, though, more than this is expected.
The first problem of packaging an application for installation arises because of the wide variety of platforms a PyQt application will run on: Classic Unix, Linux, the free BSDs, Windows in its infinite variety and finally OS X. Depending upon your target audience, one or more of these platforms can be dropped. If your application is open source, you might be able to get other developers to package your application for their platform.
The second problem is that Python has several methods of packaging applications. The standard is Distutils, which comes with the Python distribution. Then there is freeze, Gordon McMillan's Installer, Fredrik Lundh's Squeeze (which is packaged with the PythonWorks IDE), and finally Thomas Heller's py2exe (which makes use of Distutils). There are also generic commercial solutions, such as Wise or InstallShield (both for Windows) and InstallAnywhere (for all platforms that support Java). Furthermore, there are free alternatives, such as rpm or dpgk for Unix. This breadth of choice alone points to the fact that creating installation packages is a difficult problem that has yet to be solved.
Distutils is the standard Python solution and comes with Python 2.x. It appears to be more geared to distribution modules and libraries, and less to distributing applications. If you want something that generates stand-alone executables of an application, you might want to try Gordon McMillan's Installer (http://www.mcmillan-inc.com/builder.html). BlackAdder will probably provide an installation utility in a future version, and it will probably be based on Distutils.
The third problem (they do mount up) is that you cannot assume that your user has Python installed. You must choose whether you want your users to install Python themselves, or package a complete Python installation with your application. The first option is perfectly feasible on Linux, because installing Python using either rpm or apt-get is easy enough. The second option might be feasible on Windows, as Python for windows comes with a very nice and easy installer. Of course, Windows users are generally a bit lazier than Unix users, and might not want to install another package before they can start using your application.
The fourth problem is the presence, or absence, of PyQt. Again, most modern Linux distributions include PyQt, so users can just grab the rpm or deb package, and go. As for Windows, you can freely redistribute the runtime components that come with BlackAdder, if you have bought the professional version or the non-commercial PyQt and Qt libraries.
The fifth problem arises if you have used third-party modules that require separate compilation for each platform, and separate installation.
A sixth problem arises if you have written extensions in C or C++ as part of your application or library, and want to distribute those, too.
Finally, it's difficult to achieve even a little integration with the user's desktop. All user interface platforms Qt supports - Windows, KDE, Gnome, CDE, OS X and others have wildly different standards for menu options, desktop icons, mime-type integration (for those open file with application menu's). This is, perhaps, the hardest, as it requires knowledge of all relevant desktop environments.
This chapter will cover the creation of source packages, Windows installers and Unix rpms using the standard Distutils package. This requires that the user has already installed Python, PyQt, and any other libraries. The Redhat Package Manager (rpm) on Linux can be told to check for these dependencies. On Windows, it's a matter of forcing your users to read the manual. I don't describe the process of packaging your own C or C++ extensions, though it is possible. Consult the Distutils manual for more information.