If you wan't to set up a multilingual site, you should start by reading the Multilingual Guide. If you only wan't to install drupal in another language, you should read Install Drupal in another language
Related information: Drupal translations
With Drupal 8 planned to be relying even more on data from localize.drupal.org directly, the site will gain even more prominence. We can safely say though that pretty much nothing is going to change/be fixed on the site if people don't step up. Time for you to make a contribution!