In Joomla 1.7 it is possible to create your site in many languages. In short this is done like this:

1. Install your languages via the extensions installer.
2. Create the content/menus and assign them to languages.
3. Put a language switch module on your site.

See the introductory video for Joomla 1.7 multilingual possibilities:

Multilingual Joomla! demo:
http://multilingual-joomla-demo.cloudaccess.net/

Multilingual Joomla! 1.7 instructions & documentation:
http://help.joomla.org/files/EN-GB_multilang_tutorial.pdf