GkSetup has been translated into a lot of different languages already. Most translations are already included in the standard GkSetup package, including the Free-Edition downloads. New translations can be created using the UDB Editor. Please contact us before you start with a new translation to avoid duplicated work from multiple authors.
The UBD Editor comes with a readme file that explains how the translation works.
Language DLLs for the old GkSetup Versions before 2.0 are still available here.