posde,
I did a german retranslation some time ago, the ticket should still be floating around in Trac. However, it's far from perfect and additional work is needed. The original french and german translations provided by Pluto looked like being done with some automated translation service and are really bad...
powerbits,
I think there are instructions on the wiki on how to translate the UI. You are very welcome on adding more languages or improving the current translations.
br,
/chriss