There are 2 different ways to translate Simple Invoices, 1 is by using Subversion - which is a version control tool and 2 is the manual version. If your already familiar with subversion use subversion else use the Non Subversion method

refer: simple_invoices_subversion_how-to

• check out the latest code using https:// and your gmail account
• modify the existing files or add your new one (svn add)
• commit the files (svn commit -m “include a message”)
• update the Translation bug in our issue tracking system with info amount your new files/edits
  • http://code.google.com/p/simpleinvoices/issues/detail?id=21&can=2&q=

• get the latest files from
  • either from the latest version of Simple Invoices, in the lang folder
  • or if your after the most upto date files (which is recommended) copy the files from our subversion repository
    • http://simpleinvoices.googlecode.com/svn/trunk/lang/
  • english_UK will have the most upto date info: lang/en-gn/lang.php
• create/or modify the language file of your choice( ie. fr/lang.php )

• also after each variable in the lang files theres a 1 or 0
  • 1 means the variable has been translated
  • 0 means its still to be translated
  • The point to the 1 and 0 is so we can report on which files need updating
  • refer: http://code.google.com/p/simpleinvoices/source/browse/trunk/lang/lang_check.txt for a summary report of status of the lang files

• NOTE: Please save your translation files as UTF-8, if your using Windows i recommend you use textpad

(http://www.textpad.com/download/index.html#downloads), ive tried notepad/wordpad for UTF-8 and it hasn't worked correctly

• Post your new/or updated language files in Translation bug in our issue tracking system

http://code.google.com/p/simpleinvoices/issues/detail?id=21&can=2&q=

• or if you cant post to the issue tracking system as mentioned above just send me(justin@kelly.org.au) the file and i'll include in - to easy