Distribution Utilities
General distribution of Python code is typically done using the Distutils package from the standard library which can produce source and binary distributions which depend on end-users having Python already installed on their computer (with Python Eggs being a form of software distribution provided by the Distutils derivative, setuptools). Such source and binary software distributions are frequently available as operating system packages (a more general form of the term "package" referring not just to code but also to documentation, resources and other things) and can be installed using the package management infrastructure employed by various operating systems - see "System Package Distribution" below.
Executable Applications
The following projects support the production of executable application from Python scripts.
bbfreeze - create standalone executables from python scripts
esky - an auto-update framework built on top of bbfreeze
ExeMaker - creates EXE loaders for Python scripts (for Windows)
Freeze - bundled tool to build executables (Unix-only?)
py2exe - transform Python scripts into standalone Windows executable
py2app - converts Python scripts into executable Mac OS X applications
McMillan's Installer - includes notes about (other) distributing solutions
PyInstaller - derived from McMillan's installer
Installers
Installers are sometimes needed to wrap up the output of freeze tools into packages:
Inno Setup (Windows)
NSIS (Windows)
MacPython BundleBuilder (Mac OS X)
See also
deployment (an answer to the frequently asked question on the topic)
System Package Distribution
Although Distutils supports the production of some system packages, other tools exist to make such packages:
ShowMeDo video (and wiki) on how to create a Debian package (.deb) from a python program (.py). This is useful if you want to distribute to Debian based Linux Systems like Debian or Ubuntu.
PackagingGuide/Python in the Ubuntu Wiki
Distribution Using Virtualisation
It is possible to distribute entire systems which can then be run under virtualisation or as "live CD" environments. Some solutions attempt to incorporate such approaches in a way which is transparent to the user:
LINA - running Linux-based applications on other systems