Features

Translation

• Supports translation of views and db content.
• Supports pluralization, even in languages with multiple plural forms like Polish, via the String division method (’/’).
• Automatic routing to locale-specific templates (e.g. show.es-ES.rhtml).
• Automatically chooses locale-specific ActionMailer template.

Easy to Use

• It’s transparent: You’ll mostly just use Locale.set, "string".t, and translates :field. The rest is automatic.
• All translation and localization data is in three database tables: globalize_countries, globalize_languages, and globalize_translations.
• Comes with a free Currency class, especially designed for Rails. Prints out numbers correctly for each locale, and supports currency formatting (¥2300.00, 23 000,00 kr). Values are stored internally and in the database as integers, for maximum precision.

Built-in Data

• Comprehensive list of 7599 languages and 239 countries, with pluralization rules, native language names (Spanish is Español) and number formatting.
• Supplies Time#localize and Date#localize to print out times and dates in strftime format in 92 languages. Other languages can be added by simply supplying translations.

Efficiency

• Efficient querying for db translations. One DB call loads models and translations for current language.
• Additionally, there’s a piggyback feature for associations. So, Product.find(:all, :include_translated => :manufacturer) is one DB call, but gives you product.manufacturer_name in your current language.
• Caches view translations to cut down on db queries.

Databases

• Supports PostgreSQL, MySQL and Sqlite3

And, it’s ridiculously easy to add to your app.

Comparison to others

Globalize is generally said to be the most powerful all-in-one solution for Internationalization of Ruby on Rails applications.

(more to come soon … until then please refer to the comparison on the Rails wiki.)