The openInstaller project provides the framework for developers to create cross platform installations.
More about openInstaller on the home page.
Sun Java ES G11n department is already working on i18n, l10n and translation of this project.
Plain text from user interface is quite tricky to translate without knowledge of the usage. We are currently discussing convenient ways of commenting user interface resource bundles. This initiative has goal to provide translation context to the people working on the translation.
You can join the community and participate on decision making.
It's discussed on dev(at)openinstaller.dev.java.net mail alias subject "Commenting of resource bundles".