If you are prepared to take on a very small project (currently 26! messages) please reply.
This is a
GetText-style translation project. You add translations to a .po (portable object) file, which is a structured textfile. You can download a nice tool called
Poedit to do this. It's available for Mac and Windows and the basic version is free. But if you've done this sort of thing before you can of course use whatever tool you know and like.