I did a german translation that I want to share. It's the admin frontend including all installation dialogs currently except the zp-config and install instruction textfiles (I can add this in the future to make a full german version.)
Later I read on the forum/trac that there is already a localization support (my PHP-skills are sadly too basic to programm this I think) planned for future versions but I needed it to do now for a client anyway. So I want to offer my help transfering and expanding the german translation once the language support is included.

You can download it here:
zenphoto 1.0.8.2 DE
(If you find any typos, error or whatever post here please)