I made a three language web site for my friend in Vietnam (http://activeandlovingit.com/)using a WordPress plugin called WPML. The site uses English as the basic language with Vietnamese and Japanese as the translated languages. Previously I used a plugin called qTranslate but I found WPML to be superior to it in that it makes a separate URL for each language. This means better SEO with search engines, for they will index that URL. qTranslate only makes one URL for all the languages and separates them by using code in the body of the URL.
Another point, qTranslate did not display the language properly from time to time when using caching software such as W3 Total Cache. WPML does.
Unfortunately WPML seems to slow down a site with hundreds of posts like this one. I recommend using it only on site not too big. The Active and Loving it site has only 100 posts and pages.