Translate a plugin using .po .mo files

I want to translate this plugin.

The plugin has already been translated into other languages and it has .pot files for adding new languages (as far as I understood from description).

How do I create .po and .mo files for my new language and make them accessible so as to be used by the plugin? I’ve tried to define Russian language in my wp-config.php file by inserting the definition below:

define ('WPLANG', 'ru_RU');

The Editor

There are others, but this is most used: Poedit, a cross-platform gettext catalogs (.po files) editor.

The Formats

• .mo stands for Machine Object
  — compiled export of the .po file which is used by WordPress
• .po stands for Portable Object
  — editable text file with the translations strings
  — based on the master .pot file, using Update from POT file PoEdit function
  — some folks distribute this as a master file, but it should be used only for translations
• .pot stands for Portable Object Template
  — editable text file used to grab all the translatable strings from WordPress itself and Themes and Plugins, using Update from Sources PoEdit function

The Procedure

• Duplicate the .pot file and rename it to plugin-basename-lang_COUNTRY.po
• Example for the referenced plugin case: subscribe-reloaded-pt_BR.po
  — pt_BR means Portuguese Brazil, but many languages don’t have a country variation…
  — you’ll have to fill in with your own language
• WPLANG in wp-config.php file must be set to your language, e.g., pt_BR
• Every time you save the .po file, PoEdit automatically generates a .mo file, which is the one WordPress uses and basically the only one you need to upload

Observations

• If you do a full or a decent partial translation, submit it to the plugin author so he can include it in the Repository and you get credited for it
• Don’t forget to make a backup of your translation, because if you upgrade the plugin your file will be lost
• @user17078 plugin suggestion is quite nice, but I never used it much