I tried two Wordpress plugin developed for manage multilanguage content: xLanguage and Gengo. For me the first one became a synonymous of the word 'pain'. xLanguage installation has created its database table correctly but after a login my WP blowed-up.
This happened any time I tried to install a plugin and only a manual operation on DB tables saves me.
Gengo installs flawless and it implements the things you would expect from a multilanguage plugin: it's possible to associate a translation to a post and to categories and to tags and it's possible to add "translated snippets".
A translated snippet is a fragment of text you would want to translate. From Gengo administration panel you have to add the snippet and its name, its translations and then in WP template files simple insert gengo_snippet('snippet_name');.
The text fragment you added in the snippets will appear in the right language.