Windows Installer PowerShell extensions project now available on CodePlex
Heath Stewart recently wrote a blog post at http://blogs.msdn.com/heaths/archive/2007/03/14/introducing-windows-installer-powershell-extensions.aspx that introduces a new project that he published on CodePlex - the Windows Installer PowerShell Extensions (also known as PSMSI) project.
The initial version of this project, located at http://www.codeplex.com/psmsi, contains cmdlets that can be used within PowerShell to query product and patch information for installed MSI-based products. I've talked to Heath about this project, and his longer term vision includes many additional cmdlets so that these extensions can be used for a variety of Windows Installer troubleshooting tasks.
If you use PowerShell at all and/or are involved in setup development or troubleshooting, I encourage you to take a look at this project to see if you can use these extensions (and possibly contribute to enhancing them as well).