MSIDIFF Dennis Bareis
Free powerful but easy to use multiplatform html preprocessor. Includes external files. Imports SQL (and delimited text files). Useful for automated web site development and ensuring a common look and feel. Supports macros and conditionals.
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).