CGML (Celogeek Multi Languages), It’s a plugin that allow you to link many blog in different language together.
Gives WordPress developers easy access to localized country, region, language, currency, time zone, and calendar info.
Configures and installs Translate.com's Website Translator code into your WordPress site.
Substantially increase performance of localized WordPress by caching the translation (l10n) object. Supports multiple languages.
A well engineered template for creating plugins using object-oriented programming practices. Uses Settings API, multisite, i18n, PHPUnit tests.