As said in a previous article, I am convinced that part of the motivation for making package sub-systems like the Python one, which includes distutils, setuptools, etc, is that Windows users and Mac users never had the chance to use a tool that properly manages the configuration of their computer system. They just do not know what it would be like if they had at least a good package management system and do not miss it in their daily work.
I looked for Windows package managers that claim to provide features similar to Debian's dpkg+apt-get and here is what I found in alphabetical order.
AppSnap is written in Python and uses wxPython, PyCurl and PyYAML. It is packaged using Py2Exe, compressed with UPX and installed using NSIS.
It has not seen activity in the svn or on its blog since the end of 2008.
Appupdater provides functionality similar to apt-get or yum. It automates the process of installing and maintaining up to date versions of programs. It claims to be fully customizable and is licensed under the GPL.
It seems under active development at SourceForge.
Win-get is an automated install system and software repository for Microsoft Windows. It is similar to apt-get: it connects to a link repository, finds an application and downloads it before performing the installation routine (silent or standard) and deleting the install file.
It is written in pascal and is set up as a SourceForge project, but not much has been done lately.
WinLibre is a Windows free software distribution that provides a repository of packages and a tool to automate and simplify their installation.
WinLibre was selected for Google Summer of Code 2009.
I have not used any of these tools, the above is just the result of some time spent searching the web.
A more limited approach is to notify the user of the newer versions:
The appupdater project also compares itself to the programs automating the installation of software on Windows.
Some columists expect the creation of application stores replicating the iPhone one.
I once read about a project to get the Windows kernel into the Debian distribution, but can not find any trace of it... Remember that Debian is not limited to the Linux kernel, so why not think about a very improbable apt-get install windows-vista ?