Wipt
Wipt is a package management system similar to Debian APT. It allows a system administrator to create a list of URLs for MSI packages (using a simple XML file format). The applications can then be installed, removed, and upgraded using the wipt-get console application. The repository file can also contain URLs of customization transforms to be applied at installation, as well as patches to the package.
One advantage of this system is that the packages are not required to be on the same server. System administrators can create a repository consisting entirely of transforms, and direct clients to download packages directly from the vendor.
7-27-06: Wipt 1.0 Release Candidate 3 is now available for download via the following link. By default it will use the repository linked to below. You can specify a different repository on a per-machine or per-user basis by modifying HKLM\SOFTWARE\ACM\Wipt\Repositories or the same key in HKCU. More documentation will be forthcoming. Report any bugs/problems/suggestions to sigwin@acm.uiuc.edu.
Wipt requires v1.1 of the .NET Framework to be installed. If you do not have it, you can download it from Microsoft.