When You will add new store You don’t have to change anything with Your url’s. Magento will work fine as expected because url’s are stored in database per store view.
My advertisement now :
However, if You with to translate any urls in Magento to any language You like than I have made a module for that.
With it you can translate part of url - example:
It’s not only allow entering translated url’s but also change links in templates - customer will see everwhere translated url’s.
It will be available at magento connect within few weeks (I’m waiting for store to sell it officially) but if anybody need this - just email me: poczta at kamilborkowski dot pl - I can sell it with discount
Module has also “test mode” - when enabled test mode that module will work on frontend only for logged in admin so You can test it safely.