Handle multi-language

Possible solution:
This is actually very simple. One store view = one language.
You download the desired language pack. For example French(France).
You should get a file called fr_FR_default_full_package.zip (or any other archive format)
Unzip this file over the root of your Magento application.
After that go to the admin panel. System->Configuration. Select from the top-left drop-down the store view you want to be in French and under the General tab 'Locale options' set Locale as French(France).
Save and clear the cache and you should have a store view in French. As for the products and categories again is simple. Edit the product you desire, Select from the top-left drop-down the French store view and enter the French values for the text attributes.