Sunday Morning is a jQuery plugin that enables you to add stylish "content translation" features to any website.

The plugin uses the Google Translate API, so easy to use & well-documented.

jQuery Google Translate

Using various triggers -like double-click, submitting forms, hovers..- the content can be translated instantly & optionally displayed in an integrated tooltip.

Also, you can present a chic menu that asks the user "to which language the content will be translated".