The Google translator toolkit allows users to easily edit and improve automatic translations for their own use and for use by other users of the service. The tool also allows users to search through previously edited translations, to use Google’s online translation memories and multilingual glossaries and to share translated texts. Translations can also be posted directly to Wikipedia™ or Knol.
The translator toolkit supports 47 languages. Users must subscribe (free) and log in to use the service.
To learn more about it, have a look at this video tour!