If you mean http://www.google.com/language_tools I sometimes use it to translate pages from German, French etc. to English, but for changing an entire sites language, I don't think it's that accurate.
I saw some site offer different languages. Wondering how they do it. I don't think they manage separate versions for different languages.
Not totally separate versions of the website but separate versions of all the pieces of the text on the website. (eg. menus, error messages etc.)
well If you mean Google language tools then yeah it's a helpful feature but it wont help you convert the whole site to other languages while it's not that accurate in the grammar issues and so on, but it's really a grate free service.