The language packs that were available for nBill 1 have now been converted so that they will work with nBill 2. Naturally, any new features added in nBill 2 will not have been translated yet, so will remain in English. Please note, that you will need to upgrade to nBill 2.0.6 before you can install these language packs. You can download the language packs here:
http://www.nbill.co.uk/component/option,com_docman/Itemid,10/task,cat_view/gid,12/