Google set its Language detection and translation api under Ajax form, it’s a cool shortcut when you are starting multi-language interface for one your services.

demo : “language detection”
write a clause and challenge google!

demo : Translation

official website : http://code.google.com/apis/ajaxlanguage/
tutorial: http://googleajaxsearchapi.blogspot.com/2008/03/introducing-ajax-language-api-tools-for.html