bbPress.org

Get this file: http://svn.automattic.com/bbpress-i18n/pot/tags/1.0.2/bbpress.pot

Open it with PoEdit: http://www.poedit.net/download.php

Find the strings you need to change, for example, “Location” and translate them to what you need. Save the changes as a .po file (it will also create a .mo file). Copy both files to your bbpress directory into a folder called “my-languages”. If you don’t have such a folder, create it.

Change your bb-config.php file and you’re done.