Multilingual content -nodes-
Note that there is a much more detailed page about this at Getting the whole thing to work.
Enable the Translation module, then administer > access control and enable the "translate nodes" permission. Next define, in the administer > settings > content-types pages, which content types you want to have in multiple languages. This will now give a 'language' field and a 'translations' tab when creating or editing the node type(s).
When you navigate the site using multiple languages, the pages will just show the content for the chosen language plus the ones that haven't a defined language. When editing a node, you must click on 'Preview' after changing language for the right vocabularies and terms to be shown.
The multi language support is expected to work for all node types, and node listings. So far, I have not found incompatibilities with any other content type module. Please, file an issue against the project page is you find any. And yes, flexinode works with multiple languages.

For the node to translate you need to activate Tranlsation block
The Language Switcher only switches the interface, but will leave intact your original lang node.
To switch the content language of node and site, use the Translations block.
http://drupal.org/node/245831