Create or update MSI based installers for files, registry etc using an XML like script. Allows automated builds (NMAKE, ANT, NANT builds etc). For both beginners and advanced users with support via a large user group (500+ members).
MSIDIFF is freeware to compare or disassemble Windows Installer databases (a "MSI to TEXT" utility). While it is a command line based tool, the installer creates shell extensions so that it can be invoked by right clicking on a file in Explorer.