These two posts explain how to automatically translate your WordPress posts and pages into up to 12 different languages -- Arabic, Chinese (simplified and traditional), Dutch, French, German, Italian, Japanese, Korean, Portuguese, Russian and Spanish. You have a choice of machine translation services from either Google or Applied Language.
You can also provide your readers direct language translations to your site and posts on the fly! Way cool!
Javascript and instructions, including sample HTML code and working download pages, are provided to give you the capability to add language translation to your own site.
See:
http://www.mkbergman.com/?p=267 and
http://www.mkbergman.com/?p=263