There are 16 labels to be translated, currently an English and a German translation are available. If you have some time left over, help translating it on http://wiki.openstreetmap.org/wiki/OpenStreetBugs/New_Client/Translation.
Comment from Ævar Arnfjörð Bjarmason on 17 November 2009 at 18:54
Are you interested in making your map translatable via Translatewiki?We already moved Potlatch & the OSM website over there, it would be relatively easy to add something new.
Translatewiki works better with translations where the key is an abstract thing like "ui_fixed_error" instead of the original English string like "Fixed Error".
Comment from Candid Dauth on 4 December 2009 at 18:44
At the moment, Translatewiki seems to be too complicated, as translators have to register and request permission to translate. It doesn’t seem to be possible to create a new project. On the other hand the number of languages that my tools could be translated to would probably be much higher on Translatewiki because non-OpenStreetMap users could help with the translation as well.
At the moment, I prefer the OpenStreetMap wiki, as it is more newcomer-friendly.